this is to help protect against intentional or unintentional
slowloris style problems where a client keeps a tcp connection
alive but never sends any data. because grpc is great, we have
to spawn a separate goroutine for every read/write to the stream
so that we can return from the server handler to cancel it if
necessary. yep. really.
additionally, we update the rpcstatus package to do some stack
trace capture and add a Wrap method for the times where we want
to just use the existing error.
also fixes a number of TODOs where we attach status codes to the
returned errors in the endpoints.
Change-Id: Id8bb8ff84aa34e0f711b0cf9bce3908b36a1d3c1