Finer-grained access control on the teacher side

It may be useful to havea finer-grained capability structure on the teacher side, in particular in order to limit what teachers can do to the slots of other teachers.

One request runs as follows:

• "We were hoping to have a 3rd party, like a secretary, be able to mark "attend" for student appointments. This person would only be responsible for marking attend/seen for students, not putting them into a slot. Is it possible to give them "manage attend only" by cutting up some of the mod/scheduler:manageallappointments?" - "In our somewhat special circumstances, we can't give any other editing permissions to the "secretaries", which is why we need to limit them to view current slots and mark attend/seen only."