p2p: meter peer traffic, emit metered peer events (#17695)

This change extends the peer metrics collection:

- traces the life-cycle of the peers
- meters the peer traffic separately for every peer
- creates event feed for the peer events
- emits the peer events

p2p/dial.go

@@ -350,7 +350,7 @@ func (t *dialTask) dial(srv *Server, dest *enode.Node) error {
 	if err != nil {
 		return &dialError{err}
 	}
-	mfd := newMeteredConn(fd, false)
+	mfd := newMeteredConn(fd, false, dest.IP())
 	return srv.SetupConn(mfd, t.flags, dest)
 }