Reservation constraints

- 30 minutes should be the minimal reservable time
- 3 hours should be the maximal reservable time
- Reservations should only be available every fifteen minutes ('00, '15, '30, '45)
- Either a user or a band should be set during a reservation, not both
- This should be done via dropdown
- All users (except the admins) should only be able to reserve 8 hours per week and 4 hours per day. If you go over this, it counts as "overtime reservation" (Other users can overwrite it)
- The admins should be able to set these amounts
- Sanctioned users should have less available hours
- The admin should be able to set the amount based on the sanction points
- Users should not be able to make a reservation on a week, unless the admins have opened it
- The different types of reservations (normal, need to be let in, band, overtime, sanctioned, comment and admin) should appear in different color