ReservationOccurrence bulk creation and cleanup
Overlap methods added to ReservationOccurrence
Fixed ReservationOccurrence bulk creation with TZ
Generalized BarList2Dictionary helper

* Created group_list method
* Removed unnecessary class
* Renamed iterators.py
Prevent overlap checks between different rooms
Moved iterdays to indico.util.date_time with rrule
Refactored Bars and removed unncessary methods
Fixed photo_id reference in RoomMiniDetails tpl
Adapted RoomBookingCalendar to new backend
Room BookingForm populate form from request
Adapted view of BookForm page to new backend

* Adapted template
* Removed unused endpoints and methods
Booking form fields render with WTForms
Post-WIP fixes
Fixed format_time not handling timezone
RoomBooking Calendar adapted to new backend
Fixed roomselector widget small photo rendering
Booking search/creation/calendar to new DB

Creation is not finished yet and very WIP
Fix booking details/deletion, check nbp/bt
Fix typo
Show blocking bars in booking calendar/search