contractcourt: add access to full invoice registry from resolvers

Previously a function pointer was passed to chain arbitrator to avoid a
circular dependency. Now that the routetypes package exists, we can pass
the full invoice registry to chain arbitrator.

This is a preparation to be able to use other invoice registry methods
in contract resolvers.

server.go

@@ -778,7 +778,7 @@ func newServer(listenAddrs []net.Addr, chanDB *channeldb.DB, cc *chainControl,
 		},
 		DisableChannel:      s.chanStatusMgr.RequestDisable,
 		Sweeper:             s.sweeper,
-		SettleInvoice:       s.invoices.SettleInvoice,
+		Registry:            s.invoices,
 		NotifyClosedChannel: s.channelNotifier.NotifyClosedChannelEvent,
 	}, chanDB)