Add SSL mutual authentication support for rdci

The RDC API is changed to pass the certificates to the gRPC.

Add the support to add all GPUs in the host to a group. Also before
add a GPU to a group, the RDC API will verify that GPU exists or not.

Add the support to fetch the temperature metrics.

Change-Id: I5857ef03fede233d16e8b2836be120f33172da93

example/field_value_example.cc

@@ -63,7 +63,8 @@ int main(int, char **) {
     }
 
     if (standalone) {  // standalone
-        result = rdc_connect(hostIpAddress, &rdc_handle);
+        result = rdc_connect(hostIpAddress, &rdc_handle,
+            nullptr, nullptr, nullptr);
         if ( result != RDC_ST_OK ) {
             std::cout << "Error connecting to remote rdcd. Return: "
                 << rdc_status_string(result) << std::endl;