graph/db: let ForEachNodeCached maybe fetch node addresses

Here we adjust the ForEachNodeCached graph DB method to pass in a node's
addresses into the provided call-back if requested. This will allow us
to improve the performance of node/channel iteration in the autopilot
subserver.

graph/db/interfaces.go

@@ -83,11 +83,18 @@ type V1Store interface { //nolint:interfacebloat
 			*models.ChannelEdgePolicy) error, reset func()) error
 
 	// ForEachNodeCached is similar to forEachNode, but it returns
-	// DirectedChannel data to the call-back.
+	// DirectedChannel data to the call-back. If withAddrs is true, then
+	// the call-back will also be provided with the addresses associated
+	// with the node. The address retrieval will likely result in an
+	// additional round-trip to the database, so it should only be used if
+	// the addresses are actually needed.
 	//
 	// NOTE: The callback contents MUST not be modified.
-	ForEachNodeCached(ctx context.Context, cb func(node route.Vertex,
-		chans map[uint64]*DirectedChannel) error, reset func()) error
+	ForEachNodeCached(ctx context.Context, withAddrs bool,
+		cb func(ctx context.Context, node route.Vertex,
+			addrs []net.Addr,
+			chans map[uint64]*DirectedChannel) error,
+		reset func()) error
 
 	// ForEachNode iterates through all the stored vertices/nodes in the
 	// graph, executing the passed callback with each node encountered. If