autopilot: update AttachmentHeuristics with context

Continue threading context through the autopilot system and remove the
remaining context.TODOs.

autopilot/top_centrality.go

@@ -51,11 +51,9 @@ func (g *TopCentrality) Name() string {
 // As our current implementation of betweenness centrality is non-incremental,
 // NodeScores will recalculate the centrality values on every call, which is
 // slow for large graphs.
-func (g *TopCentrality) NodeScores(graph ChannelGraph, chans []LocalChannel,
-	chanSize btcutil.Amount, nodes map[NodeID]struct{}) (
-	map[NodeID]*NodeScore, error) {
-
-	ctx := context.TODO()
+func (g *TopCentrality) NodeScores(ctx context.Context, graph ChannelGraph,
+	chans []LocalChannel, chanSize btcutil.Amount,
+	nodes map[NodeID]struct{}) (map[NodeID]*NodeScore, error) {
 
 	// Calculate betweenness centrality for the whole graph.
 	if err := g.centralityMetric.Refresh(ctx, graph); err != nil {