This adds a simple schema for build telemetry data. We can make it more
restrictive once we have a better feeling for what kind of data we want
to submit.
This also moves more common data about the system to the telemetry handler.
We leave psutil derivied information in the resource usage data as not every
system will have psutil installed.
MozReview-Commit-ID: CFRq1Ow6AOf
--HG--
extra : rebase_source : 3022d8f5d20e3d4f9dc871cf2217a6dad2f22e05
