Add language configuration and Spanish translation

This commits configures and sets up flask-babel and adds Spanish po
file. Flask-babel is already a dependency so this commits no needs to
add it.

Users can edit ogcp.json to choose between English or Spanish. After
changing the language in the configuration file, users must restart ogcp
service.

Instructions to generate translation files, inspired by
https://flask-babel.tkte.ch/:

1. Download ogcp source code.

   git clone git://git.soleta.eu/ogCP /path/to/ogcp

2. Create a python virtual environment.

   python3 -m venv /path/to/new/venv

3. Activate the virtual environment.

   source /path/to/new/venv/bin/activate

4. Install dependencies to the virtual environment.

   cd /path/to/ogcp
   pip3 install -r requirements.txt

5. Extract ogcp strings.

   cd /path/to/ogcp/ogcp
   pybabel extract -F babel.cfg -k _l -o messages.pot .

   NOTE: "-k _l" is needed to extract strings which use lazy
   translations.

6. Create or update translation files.

   a. Create translation file. This example creates a french translation
   file.

      pybabel init -i messages.pot -d translations -l fr

   b. Update translation files. You need to do this when ogcp strings
   change and want to update current supported languages.

      pybabel update -i messages.pot -d translations

7. Edit the translations .po file as needed. Example route:
   /path/to/ogcp/ogcp/translations/fr/LC_MESSAGES/messages.po.

8. Compile translations.

   pybabel compile -d translations

9. Launch ogcp and check the translations.

   cd /path/to/ogcp
   pip3 install -r requirements.txt

10. Commit and push .po files with translation changes.

4 files changed, 522 insertions, 0 deletions

diff --git a/ogcp/__init__.py b/ogcp/__init__.py
index 23d6769..5d5f3e4 100644
--- a/ogcp/__init__.py
+++ b/ogcp/__init__.py
@@ -20,4 +20,8 @@ csrf = CSRFProtect(app)
 bootstrap = Bootstrap(app)
 
 
+@babel.localeselector
+def localeselector():
+    return app.config.get('LANG', 'en')
+
 import ogcp.views
diff --git a/ogcp/babel.cfg b/ogcp/babel.cfg
new file mode 100644
index 0000000..f0234b3
--- /dev/null
+++ b/ogcp/babel.cfg
@@ -0,0 +1,3 @@
+[python: **.py]
+[jinja2: **/templates/**.html]
+extensions=jinja2.ext.autoescape,jinja2.ext.with_
diff --git a/ogcp/cfg/ogcp.json b/ogcp/cfg/ogcp.json
index 3f8a82c..0a47a07 100644
--- a/ogcp/cfg/ogcp.json
+++ b/ogcp/cfg/ogcp.json
@@ -2,6 +2,7 @@
 	"IP": "127.0.0.1",
 	"PORT": 8888,
 	"API_TOKEN": "c3fe7bb0395747ec42a25df027585871",
+	"LANG": "en",
 	"USERS": [
 		{
 			"USER": "admin",
diff --git a/ogcp/translations/es/LC_MESSAGES/messages.po b/ogcp/translations/es/LC_MESSAGES/messages.po
new file mode 100644
index 0000000..88de07f
--- /dev/null
+++ b/ogcp/translations/es/LC_MESSAGES/messages.po
@@ -0,0 +1,514 @@
+# Spanish translations for OgCP.
+# Copyright (C) 2021 Soleta Networks
+# This file is distributed under the same license as the OgCP project.
+# Soleta Networks <opengnsys@soleta.eu>, 2021.
+#
+msgid ""
+msgstr ""
+"Project-Id-Version: 1.0.0\n"
+"Report-Msgid-Bugs-To: opengnsys@soleta.eu\n"
+"POT-Creation-Date: 2022-01-11 16:10+0000\n"
+"PO-Revision-Date: 2021-12-23 16:47+0100\n"
+"Last-Translator: Soleta Networks <opengnsys@soleta.eu>\n"
+"Language: es\n"
+"Language-Team: es <opengnsys@soleta.eu>\n"
+"Plural-Forms: nplurals=2; plural=(n != 1)\n"
+"MIME-Version: 1.0\n"
+"Content-Type: text/plain; charset=utf-8\n"
+"Content-Transfer-Encoding: 8bit\n"
+"Generated-By: Babel 2.8.0\n"
+
+#: views.py:82
+msgid "Please, select at least {} element(s)"
+msgstr "Por favor, seleccione al menos {} elemento(s)"
+
+#: views.py:86
+msgid "No more than {} element(s) can be selected for the given action"
+msgstr "No se pueden seleccionar más de {} elemento(s) para la acción dada"
+
+#: views.py:174
+msgid "Incorrect password"
+msgstr "Contraseña incorrecta"
+
+#: views.py:176
+msgid "Incorrect user name"
+msgstr "Nombre de usuario incorrecto"
+
+#: views.py:275
+msgid "Wake On Lan request sent successfully"
+msgstr "Wake On Lan enviado con éxito"
+
+#: views.py:436
+msgid "Computers have different partition setup"
+msgstr "Los ordenadores tienen diferentes configuraciones de partición"
+
+#: views.py:440
+msgid "ogServer was unable to obtain setup of selected computer {}"
+msgstr "ogServer no pudo obtener la configuración del ordenador seleccionado {}"
+
+#: views.py:443
+msgid "Disk: {} | Part: {}"
+msgstr "Disco: {} | Partición: {}"
+
+#: views.py:488
+msgid "Software profile request sent successfully"
+msgstr "Solicitud de perfil de software enviado con éxito"
+
+#: views.py:490
+msgid "Error processing software profile request: ({})"
+msgstr "Error procesando la solicitud de perfil de software: ({})"
+
+#: views.py:640 views.py:768 views.py:783 views.py:915
+msgid "OgServer replied with a non ok status code"
+msgstr "OgServer respondió con un código de estado de error"
+
+#: views.py:642 views.py:917
+msgid "Delete client request processed successfully"
+msgstr "Solicitud de eliminar cliente procesada con éxito"
+
+#: views.py:655
+msgid "Client set boot mode request sent successfully"
+msgstr "Solicitud del cambio del modo de inicio del cliente enviado con éxito"
+
+#: views.py:657 views.py:687 views.py:694
+msgid "Ogserver replied with status code not ok"
+msgstr "OgServer respondió con el código de estado de error"
+
+#: views.py:684
+msgid "Client set ogLive request sent successfully"
+msgstr "Solicitud de cambio de ogLive enviada con éxito"
+
+#: views.py:770 views.py:785
+msgid "Refresh request processed successfully"
+msgstr "Solicitud de actualización procesada con éxito"
+
+#: views.py:797
+msgid "Server replied with error code when adding the center"
+msgstr "El servidor respondió con el código de error al agregar el centro."
+
+#: views.py:800
+msgid "Center added successfully"
+msgstr "Centro añadido con éxito"
+
+#: views.py:813
+msgid "Server replied with error code when deleting the center"
+msgstr "El servidor respondió con el código de error al eliminar el centro"
+
+#: views.py:816
+msgid "Center deleted successfully"
+msgstr "Centro eliminado con éxito"
+
+#: views.py:835
+msgid "Server replied with error code when adding the room"
+msgstr "El servidor respondió con el código de error al agregar la sala."
+
+#: views.py:837
+msgid "Room added successfully"
+msgstr "Sala añadida con éxito"
+
+#: views.py:854
+msgid "Server replied with error code when deleting the room"
+msgstr "El servidor respondió con el código de error al eliminar la sala."
+
+#: views.py:857
+msgid "Room deleted successfully"
+msgstr "Sala eliminada con éxito"
+
+#: forms/action_forms.py:19 forms/action_forms.py:27 forms/action_forms.py:57
+#: templates/actions/hardware.html:14
+msgid "Type"
+msgstr "Tipo"
+
+#: forms/action_forms.py:22 forms/action_forms.py:131 forms/action_forms.py:136
+#: forms/action_forms.py:145 forms/action_forms.py:150
+msgid "Submit"
+msgstr "Enviar"
+
+#: forms/action_forms.py:25 forms/action_forms.py:70 forms/action_forms.py:81
+msgid "Partition"
+msgstr "Partición"
+
+#: forms/action_forms.py:43
+msgid "Filesystem"
+msgstr "Sistema de ficheros"
+
+#: forms/action_forms.py:51
+msgid "Size (KB)"
+msgstr "Tamaño (KB)"
+
+#: forms/action_forms.py:52
+msgid "Format"
+msgstr "Formatear"
+
+#: forms/action_forms.py:66 templates/commands.html:25
+msgid "Refresh"
+msgstr "Actualizar"
+
+#: forms/action_forms.py:71
+msgid "View"
+msgstr "Vista"
+
+#: forms/action_forms.py:72
+msgid "Update"
+msgstr "Actualizar"
+
+#: forms/action_forms.py:76
+msgid "Session"
+msgstr "Sesión"
+
+#: forms/action_forms.py:77
+msgid "Run"
+msgstr "Lanzar"
+
+#: forms/action_forms.py:82
+msgid "Image"
+msgstr "Imagen"
+
+#: forms/action_forms.py:83
+msgid "Method"
+msgstr "Método"
+
+#: forms/action_forms.py:85
+msgid "Restore"
+msgstr "Restaurar"
+
+#: forms/action_forms.py:88 forms/action_forms.py:154
+msgid "Name"
+msgstr "Nombre"
+
+#: forms/action_forms.py:89
+msgid "IP"
+msgstr "IP"
+
+#: forms/action_forms.py:90
+msgid "MAC"
+msgstr "MAC"
+
+#: forms/action_forms.py:91
+msgid "Serial Number"
+msgstr "Número de serie"
+
+#: forms/action_forms.py:92 forms/action_forms.py:143
+msgid "Netmask"
+msgstr "Máscara de red"
+
+#: forms/action_forms.py:93 forms/action_forms.py:116
+msgid "ogLive"
+msgstr "ogLive"
+
+#: forms/action_forms.py:95
+msgid "Remote"
+msgstr "Remoto"
+
+#: forms/action_forms.py:96
+msgid "Maintenance"
+msgstr "Mantenimiento"
+
+#: forms/action_forms.py:97
+msgid "Interface"
+msgstr "Interfaz"
+
+#: forms/action_forms.py:101
+msgid "Driver"
+msgstr "Controlador"
+
+#: forms/action_forms.py:103
+msgid "Repository"
+msgstr "Repositorio"
+
+#: forms/action_forms.py:105 forms/action_forms.py:148
+msgid "Room"
+msgstr "Sala"
+
+#: forms/action_forms.py:106
+msgid "Boot Mode"
+msgstr "Modo de arranque"
+
+#: forms/action_forms.py:107 forms/action_forms.py:125
+msgid "Create"
+msgstr "Crear"
+
+#: forms/action_forms.py:111
+msgid "Boot mode"
+msgstr "Modo de arranque"
+
+#: forms/action_forms.py:112 forms/action_forms.py:117
+msgid "Ok"
+msgstr "OK"
+
+#: forms/action_forms.py:121
+msgid "OS"
+msgstr "SO"
+
+#: forms/action_forms.py:122
+msgid "Image name"
+msgstr "Nombre de la imagen"
+
+#: forms/action_forms.py:124
+msgid "Description"
+msgstr "Descripción"
+
+#: forms/action_forms.py:128
+msgid "Center name"
+msgstr "Nombre del centro"
+
+#: forms/action_forms.py:130
+msgid "Comment"
+msgstr "Comentario"
+
+#: forms/action_forms.py:134 forms/action_forms.py:139
+msgid "Center"
+msgstr "Centro"
+
+#: forms/action_forms.py:141
+msgid "Room name"
+msgstr "Nombre de la sala"
+
+#: forms/action_forms.py:153
+msgid "Id"
+msgstr "Id"
+
+#: forms/action_forms.py:155
+msgid "Size (GiB)"
+msgstr "Tamaño (GiB)"
+
+#: forms/action_forms.py:156
+msgid "Datasize (GiB)"
+msgstr "Tamaño de los datos (GiB)"
+
+#: forms/action_forms.py:157
+msgid "Modified"
+msgstr "Modificado"
+
+#: forms/action_forms.py:158
+msgid "Permissions"
+msgstr "Permisos"
+
+#: forms/action_forms.py:159
+msgid "Software id"
+msgstr "ID de software"
+
+#: forms/auth.py:19
+msgid "User"
+msgstr "Usuario"
+
+#: forms/auth.py:23
+msgid "Password"
+msgstr "Contraseña"
+
+#: forms/auth.py:27 templates/nav.html:41
+msgid "Login"
+msgstr "Acceso"
+
+#: templates/commands.html:19
+msgid "Power on (WoL)"
+msgstr "Encendido (WoL)"
+
+#: templates/commands.html:21
+msgid "Power off"
+msgstr "Apagado"
+
+#: templates/commands.html:23
+msgid "Reboot"
+msgstr "Reiniciar"
+
+#: templates/commands.html:27
+msgid "Hardware"
+msgstr "Hardware"
+
+#: templates/commands.html:29
+msgid "Software"
+msgstr "Software"
+
+#: templates/actions/session.html:6 templates/commands.html:31
+msgid "Start session"
+msgstr "Iniciar sesión"
+
+#: templates/commands.html:33
+msgid "Restore Image"
+msgstr "Restaurar imagen"
+
+#: templates/commands.html:35
+msgid "Partition & Format"
+msgstr "Particionar y formatear"
+
+#: templates/actions/client_details.html:6 templates/commands.html:37
+msgid "Client details"
+msgstr "Detalles del cliente"
+
+#: templates/commands.html:39
+msgid "Create image"
+msgstr "Crear imagen"
+
+#: templates/commands.html:41
+msgid "Set boot mode"
+msgstr "Seleccionar el modo de arranque"
+
+#: templates/commands.html:43
+msgid "Set ogLive"
+msgstr "Seleccionar ogLive"
+
+#: templates/commands.html:45
+msgid "Log"
+msgstr "Log"
+
+#: templates/commands.html:47
+msgid "Real time log"
+msgstr "Log en tiempo real"
+
+#: templates/dashboard.html:9
+msgid "Connected clients (ogClient)"
+msgstr "Clientes conectados (ogClient)"
+
+#: templates/dashboard.html:21
+msgid "Latest images"
+msgstr "Últimas imágenes"
+
+#: templates/dashboard.html:40
+msgid "Disk stats"
+msgstr "Estadisticas de disco"
+
+#: templates/dashboard.html:46
+msgid "Disk size"
+msgstr "Capacidad del disco"
+
+#: templates/dashboard.html:49
+msgid "used"
+msgstr "ocupado"
+
+#: templates/dashboard.html:52
+msgid "available"
+msgstr "disponible"
+
+#: templates/dashboard.html:55
+msgid "use"
+msgstr "ocupado"
+
+#: templates/dashboard.html:74
+msgid "Number of images"
+msgstr "Número de imágenes"
+
+#: templates/dashboard.html:93
+msgid "default"
+msgstr "predeterminado"
+
+#: templates/error.html:6
+msgid "Error!"
+msgstr "¡Error!"
+
+#: templates/actions/image_details.html:6 templates/images.html:28
+msgid "Image details"
+msgstr "Detalles de la imagen"
+
+#: templates/images.html:30
+msgid "Delete image"
+msgstr "Eliminar Imagen"
+
+#: templates/nav.html:11
+msgid "Dashboard"
+msgstr "Panel principal"
+
+#: templates/nav.html:14
+msgid "Scopes"
+msgstr "Ámbito"
+
+#: templates/nav.html:17
+msgid "Commands"
+msgstr "Comandos"
+
+#: templates/nav.html:20
+msgid "Images"
+msgstr "Imágenes"
+
+#: templates/nav.html:23
+msgid "Tasks"
+msgstr "Tareas"
+
+#: templates/nav.html:26
+msgid "Schedule"
+msgstr "Programaciones"
+
+#: templates/nav.html:35
+msgid "Logout"
+msgstr "Cerrar sesión"
+
+#: templates/scopes.html:19
+msgid "Add client"
+msgstr "Añadir cliente"
+
+#: templates/scopes.html:21
+msgid "Add room"
+msgstr "Añadir sala"
+
+#: templates/scopes.html:23
+msgid "Add center"
+msgstr "Añadir centro"
+
+#: templates/scopes.html:25
+msgid "Delete client"
+msgstr "Eliminar cliente"
+
+#: templates/scopes.html:27
+msgid "Delete room"
+msgstr "Eliminar sala"
+
+#: templates/scopes.html:29
+msgid "Delete center"
+msgstr "Eliminar centro"
+
+#: templates/actions/add_center.html:6
+msgid "Add center form"
+msgstr "Formulario para añadir un centro"
+
+#: templates/actions/add_room.html:6
+msgid "Add room form"
+msgstr "Formulario para añadir una sala"
+
+#: templates/actions/delete_center.html:6
+msgid "Delete center form"
+msgstr "Formulario para eliminar un centro"
+
+#: templates/actions/delete_room.html:6
+msgid "Delete room form"
+msgstr "Formulario para eliminar una sala"
+
+#: templates/actions/hardware.html:6
+msgid "Hardware inventory"
+msgstr "Inventario de hardware"
+
+#: templates/actions/hardware.html:13
+msgid "Item"
+msgstr "Articulo"
+
+#: templates/actions/image_create.html:6
+msgid "Create a partition image"
+msgstr "Crear una imagen de partición"
+
+#: templates/actions/setup.html:5
+msgid "Partition and Format"
+msgstr "Partición y formato"
+
+#: templates/actions/setup.html:47
+msgid "Remove"
+msgstr "Eliminar"
+
+#: templates/actions/setup.html:64
+msgid "Change disk"
+msgstr "Cambiar de disco"
+
+#: templates/actions/setup.html:68
+msgid "Add a new partition"
+msgstr "Añadir una nueva partición"
+
+#: templates/actions/setup.html:72
+msgid "Accept"
+msgstr "Aceptar"
+
+#: templates/actions/software.html:6
+msgid "Software Inventory"
+msgstr "Inventario de software"
+
+#: templates/actions/legacy/log.html:6
+msgid "Client log"
+msgstr "Registro de clientes"
+