Add an option for staff to reactivate a room

Summary

In the case of a patient (or staff member) accidentally hitting the "end call" button, the current system won't allow for the connection to be re-established. Both because the room will be deactivated (see !158 (merged)) and the Jitsi room configuration won't allow it (with the password having already been set once).

Reasoning

It would be nice to still be able to create a new room in these cases, so that not a full slot is lost when this happens by accident.