add room info for APs to support monitoring maps

[davidelang]

extend PR #677 to have room/building specific information (similar to the file in #585 )

x/y coordinates in the apuse file should be room relative in feet

the room file should have the room dimensions, which map the room is on, and the map coordinates of the room (allowing for room and coordinates in apuse can be converted to coordinates on the map

consider also indicating what subnet should be used (by reference or by listing the subnet) so that we can either auto-allocate IP addresses, or validate that the IP address is correct for the building it's in. This will be less of a problem with the new file layout