Implement the APIs for gRPC calls in client/server

Implement the APIs defined in the RdcStandaloneHandler to make gRPC call to daemon

Implement the APIs defined in the RdcAPIServiceImpl to handle the gRPC calls in daemon

Add two APIs to get all GPU groups and field groups: rdc_group_get_all_ids()
and rdc_group_field_all_ids()
Those two APIs are required by the rdci group and fieldgroup
sub-modules.

Change-Id: I066091423146dea180c16af212688ed43dc44611

include/rdc_lib/impl/RdcCacheManagerImpl.h

@@ -44,9 +44,9 @@ typedef std::map<RdcFieldKey, std::vector<RdcCacheEntry>> RdcCacheSamples;
 
 class RdcCacheManagerImpl: public RdcCacheManager {
  public:
-    rdc_status_t rdc_get_latest_value_for_field(uint32_t gpu_index,
+    rdc_status_t rdc_field_get_latest_value(uint32_t gpu_index,
                 uint32_t field, rdc_field_value* value) override;
-    rdc_status_t rdc_get_field_value_since(uint32_t gpu_index, uint32_t field,
+    rdc_status_t rdc_field_get_value_since(uint32_t gpu_index, uint32_t field,
                 uint64_t since_time_stamp, uint64_t *next_since_time_stamp,
                 rdc_field_value* value) override;
     rdc_status_t rdc_update_cache(uint32_t gpu_index,