fundingmanager+server: define MaxPendingChans. RejectPush in funding config

This commit makes the funding manager access the MaxPendingChannels and
RejectPush values from the fundingConfig instead of the global config
struct.

Done to avoid sharing state between tests.

server.go

@@ -1051,6 +1051,8 @@ func newServer(listenAddrs []net.Addr, chanDB *channeldb.DB,
 		ZombieSweeperInterval:  1 * time.Minute,
 		ReservationTimeout:     10 * time.Minute,
 		MinChanSize:            btcutil.Amount(cfg.MinChanSize),
+		MaxPendingChannels:     cfg.MaxPendingChannels,
+		RejectPush:             cfg.RejectPush,
 		NotifyOpenChannelEvent: s.channelNotifier.NotifyOpenChannelEvent,
 	})
 	if err != nil {