Lock appointments
We have staff change appointments that we do not want them to change.
Add a feature called "locked appointments".
People with this security right can lock an appointment.
Locked appointments can only be changed by people with
the edit locked appointment right, or otherwise the appointments
they locked.
Add security rights called:
locked appointments: lock-only-mine (only allowed to lock, edit and unlock appts this user made)
locked appointments: lock-any (allowed to lock, edit and unlock appointments that any user made or locked)
Guest
