Add address to return value when requesting mne

Description

This is needed to be able to build automatic routing requets in DQ. Tested like this:

controller/northbound/server/networkElement.go

@@ -133,6 +133,8 @@ func (n *NetworkElementServer) Get(ctx context.Context, request *mnepb.GetReques
 		return nil, status.Errorf(codes.Aborted, "%v", err)
 	}
 
+	mne.TransportAddress = networkElement.TransportAddress()
+
 	return &mnepb.GetResponse{
 		Timestamp: time.Now().UnixNano(),
 		Pnd: &ppb.PrincipalNetworkDomain{