filter: add grpc upstream stats (#10748)

* stats: add upstream_rq_time by grpc methods

Signed-off-by: Patrik Cyvoct <patrik@ptrk.io>

Mirrored from https://github.com/envoyproxy/envoy @ 4a705335f29d37c93d43191c23e562c2255c7b21

envoy/extensions/filters/http/grpc_stats/v3/config.proto

@@ -54,6 +54,14 @@ message FilterConfig {
     //   `envoy.deprecated_features.grpc_stats_filter_enable_stats_for_all_methods_by_default`.
     google.protobuf.BoolValue stats_for_all_methods = 3;
   }
+
+  // If true, the filter will gather a histogram for the request time of the upstream.
+  // It works with :ref:`stats_for_all_methods
+  // <envoy_api_field_extensions.filters.http.grpc_stats.v3.FilterConfig.stats_for_all_methods>`
+  // and :ref:`individual_method_stats_allowlist
+  // <envoy_api_field_extensions.filters.http.grpc_stats.v3.FilterConfig.individual_method_stats_allowlist>` the same way
+  // request_message_count and response_message_count works.
+  bool enable_upstream_stats = 4;
 }
 
 // gRPC statistics filter state object in protobuf form.