Resolve "Deactivate room after patient leaves"

What does this MR do?

This MR introduces a new route /connect/patient/<tablet-path>/close-room that signals that the patient has left the room. For this, I introduce a new state (CLOSED) and rename the old CLOSED state to UNINITIALIZED. This way, we can differentiate between situations where the room hasn't been initialized yet and situations where the patient had left the room. Note that we should, at some point, add functionality to allow staff to reactivate a room, in the case this was erroneously done by the patient. See #177 (closed) for this.

In any case, this change should fix the issue where guests still saw the yellow popup even though their call was ended.

Closes #127 (closed)

Closes #70 (closed)

Does this MR meet the acceptance criteria?

• I have added tests to validate the new functionality.
• I have updated the documentation accordingly.
• I have added translations for all new client-side text.