Converts Azure Direct Method calls into mOS RPC calls.
Azure DM method name becomes RCP method name, payload becomes method args.
Since DM is a one way mechanism (cloud calls device), outgoing requests are rejected.
It sould be possible to support RPC over cloud-to-device and device-to-cloud messaging.
Unlike DM, it could be bi-directional, with device initiating the request.
This is no implemented yet.