REST API for adding builds, machines and runconfigs

REST API for these core functionalities would be really nice to have, especially in distributed testing environment.

I've already started working on it, but I see some difficulties, like API for adding test_runs/runconfigs. I think we should move some logic of run_import.py to some other module, make it more generic and reuse it for adding runs via script and API. Anyway, what do you think about API for these things? How would you @mupuf handle this?