Add comparison ops for roombookings

Add operation(s) that take the results of the operations for getting termtime room bookings and booker room_bookings, compare them and create new state, say:

• comparison.roombookings.create
• comparison.roombookings.update

Note: this is Booker bookings to TermTime roombookings sync, not TermTime events to Booker bookings

UPDATE: just tests need adding to WIP