Handle deactivated users

[drygdryg]

It is required to deactivate (or lock) the user if it is deactivated in the RC. It looks like, this should be done after the migration of messages, because deactivating a Matrix user causes an exit from all rooms.
The activity status is stored in the active field in the users collection documents.

[drygdryg]

Perhaps we shouldn't deactivate the user in Matrix, because this will cause him to exit all rooms, but in Rocket.Chat deactivated the user retains membership in the rooms.
Probably we should lock the account or deauthorize user from all devices instead.