Ban and unban peers at the swarm level (#3653)

## Issue Addressed

I missed this from #3491. peers were being banned at the behaviour level only. The identify errors are explained by this as well

## Proposed Changes

Add banning and unbanning 

## Additional Info

Befor,e having tests that catch this was hard because the swarm was outside the behaviour. We could now have tests that prevent something like this in the future

Author: divagant-martian

beacon_node/lighthouse_network/src/service/mod.rs

@@ -1342,10 +1342,12 @@ impl<AppReqId: ReqId, TSpec: EthSpec> Network<AppReqId, TSpec> {
                 Some(NetworkEvent::PeerDisconnected(peer_id))
             }
             PeerManagerEvent::Banned(peer_id, associated_ips) => {
+                self.swarm.ban_peer_id(peer_id);
                 self.discovery_mut().ban_peer(&peer_id, associated_ips);
                 Some(NetworkEvent::PeerBanned(peer_id))
             }
             PeerManagerEvent::UnBanned(peer_id, associated_ips) => {
+                self.swarm.unban_peer_id(peer_id);
                 self.discovery_mut().unban_peer(&peer_id, associated_ips);
                 Some(NetworkEvent::PeerUnbanned(peer_id))
             }