Additional networking metrics (#2549)

Adds additional metrics for network monitoring and evaluation.


Co-authored-by: Mark Mackey <mark@sigmaprime.io>

beacon_node/http_metrics/tests/tests.rs

@@ -25,6 +25,7 @@ async fn returns_200_ok() {
             chain: None,
             db_path: None,
             freezer_db_path: None,
+            gossipsub_registry: None,
             log,
         });