Implement the gRPC APIs for the job stats

Add the job stats APIs in the rdc_api_service at the server side rdcd
Add the job stats APIs for the RdcStandaloneHandler at the client side
Make the load librdc.so and librdc_client.so thread safe.
Impelement async update all fields in RdcEmbeddedHandler.

Change-Id: I659d91efb32d1094d3b7f0f2cec39518cd7336ce

example/job_stats_example.cc

@@ -66,7 +66,7 @@ int main(int, char **) {
             goto cleanup;
         }
     } else {  // embedded
-        result = rdc_start_embedded(RDC_OPERATION_MODE_AUTO, &rdc_handle);
+        result = rdc_start_embedded(RDC_OPERATION_MODE_MANUAL, &rdc_handle);
         if (result != RDC_ST_OK) {
             std::cout << "Error starting embedded RDC engine. Return: "
                 << rdc_status_string(result) << std::endl;