Assigning rooms for ICBD interviews

Currently, only timeslots are reserved with ICBD interview events. Rooms are not, so we accidentally double-booked one. It should become part of it somehow.

I personally believe that the timeslot system is already kinda messy (the schema is kinda chaotic), so adding another axis of messiness is ehhh. I think we'd have to plan this out a decent amount before just implementing it.