graph/db: version cacheable iteration methods

Add gossip version parameters to ForEachNodeCacheable and
ForEachChannelCacheable in the Store interface and both implementations.

Thread the version through SQL helpers and update call sites/tests
accordingly.

server.go

@@ -1128,7 +1128,7 @@ func newServer(ctx context.Context, cfg *Config, listenAddrs []net.Addr,
 		DefaultRoutingPolicy: cc.RoutingPolicy,
 		ForAllOutgoingChannels: func(ctx context.Context,
 			cb func(*models.ChannelEdgeInfo,
-			*models.ChannelEdgePolicy) error,
+				*models.ChannelEdgePolicy) error,
 			reset func()) error {
 
 			return s.v1Graph.ForEachNodeChannel(