Remove import of deleted module
Check booking/prebooking permissions when booking
Some improvements in the new booking RH
Move reservation creation into Reservation class
Use WTForms for book/prebook buttons
Holiday validation uses now date_time utils
Fixed messagebox weird padding
Pre-booking conflict check moved

* Pre-booking conflict warning appears now next to confirmation button
* Refactored overlapping methods in Reservation/ReservationOccurrences
* Removed old template and RH