Revert "Remove room lock, not that usefull now that you can use a password"

This reverts commit 25f260269400edfd63aacefc145b7dee79ff327e.

Locking can still be usefull to prevent participant to join, event is they know the pass

Conflicts:
	public/js/vroom.js
Move lock button at the top of the conf menu
Prevent owner to be locked out of its own room
If the room was locked when he left