Ensure racks in different rooms are distinct

[perigrin]

Rack names are only guaranteed unique per room, so any time we have a listing of racks in different rooms combined we need to ensure that the difference is noted.

This bit me recently in Conch-UI, so this ticket is here to help ensure it doesn't happen in Kosh.

[karenetheridge]

rack names are only useful when included with the room name, so it would make sense to either nest racks under rooms -- otherwise, the room name must be included with the rack name (e.g. "DC12:1F:211250:0101").