live: add cache contents to the /refresh payload

Add the list of images in the client's cache partition in the
payload sent to the server.
The information sent is a list of {image_name, img_size, checksum}
elements where img_size is the size of the respective image in bytes.

Resquest response structure:
{
    ...
    'cache': [
        {'name': 'windows.img', 'size': 2432370213, checksum: '5d4dcc677bc19f40a647d0002f4ade90'},
        {'name': 'linux.img', 'size': 243234534213, checksum: '3eb22f888f88a55ad954f55644e1192e'}
    ]
    ...
}

0 files changed, 0 insertions, 0 deletions