nuxeo-quota addon: fix inconsistency in computation of trash size and live documents size

How to reproduce:

• empty repository
• create a `File` document with a 6611 bytes file (screenshot-1)
• create 2 versions of the `File` document previously created (screenshot-2)
• delete the `File` (move to trash) (screenshot-3)
• create another `File` document with a 53531 bytes file (screenshot-4)

Live documents size should be 53531 bytes but it is not because versions' size was added to trash size.
So when a document is moved to the trash, only its inner size should be moved to its trash size, not its total size.

Live document size computation should follow the following formula:

live document size = total size - versions size - trash size