In order to list instances in the brave new world of cellsv2 we must
aggregate results from the build_requests table in the api cell, cell0,
and the single(atm) actual cell. Note that there are no plans to make
filtering/sorting a list of instances work across multiple cells.
Change-Id: I625c7714fb04eb2bf07695fd7ec053a2f32c62bc
Partially-implements: bp add-buildrequest-obj
Partially-implements: bp cells-scheduling-interaction
Depends-On: I090d5994c3077d86c60457e4c16a03d35e0c409c