Incomplete columns populated for racks in build view

[karenetheridge]

browse -> select a build -> view all racks. The datacenter room column is not populated, because that data would be pulled from GET /room which is sysadmin-only. Instead, this view should show the columns that are included in the response of GET /build/:id_or_name/racks, such as full_rack_name and datacenter_room_alias.

(related to #198.)