Add a flag to disable peer scoring (#4135)

## Issue Addressed

N/A

## Proposed Changes

Adds a flag for disabling peer scoring. This is useful for local testing and testing small networks for new features.

lighthouse/tests/beacon_node.rs

@@ -1045,6 +1045,13 @@ fn disable_discovery_flag() {
         .with_config(|config| assert!(config.network.disable_discovery));
 }
 #[test]
+fn disable_peer_scoring_flag() {
+    CommandLineTest::new()
+        .flag("disable-peer-scoring", None)
+        .run_with_zero_port()
+        .with_config(|config| assert!(config.network.disable_peer_scoring));
+}
+#[test]
 fn disable_upnp_flag() {
     CommandLineTest::new()
         .flag("disable-upnp", None)