Request Handling: Implement support for background proccessing of telemetry reports once they have been staged

[rtamalin]

Currently our telemetry report request handling workflow stages the telemetry report in the persistent data store, and processes the report to extract and persistently store the data items in the Telemetry DB, deleting the staged report, before completing the request to the client.

In the long run the report request handling should trigger background processing to do the extraction and persistent storing of the telemetry data items, so that the server can respond immediately to the client once we have staged the telemetry report.