channeldb: add storing of node signature and add edge signature

In order to properly announce the channel the announcements proofs
should be persistent in boltdb.

routing/notifications_test.go

@@ -49,6 +49,7 @@ func createGraphNode() (*channeldb.LightningNode, error) {
 		PubKey:     priv.PubKey(),
 		Color:      color.RGBA{1, 2, 3, 0},
 		Alias:      "kek" + string(pub[:]),
+		AuthSig:    testSig,
 		Features:   testFeatures,
 	}, nil
 }
@@ -79,6 +80,7 @@ func randEdgePolicy(chanID lnwire.ShortChannelID,
 	node *channeldb.LightningNode) *channeldb.ChannelEdgePolicy {
 
 	return &channeldb.ChannelEdgePolicy{
+		Signature:                 testSig,
 		ChannelID:                 chanID.ToUint64(),
 		LastUpdate:                time.Unix(int64(prand.Int31()), 0),
 		TimeLockDelta:             uint16(prand.Int63()),

routing/pathfind_test.go

@@ -163,6 +163,7 @@ func parseTestGraph(path string) (*channeldb.ChannelGraph, func(), aliasMap, err
 		}
 
 		dbNode := &channeldb.LightningNode{
+			AuthSig:    testSig,
 			LastUpdate: time.Now(),
 			Addresses:  testAddrs,
 			PubKey:     pub,
@@ -257,6 +258,7 @@ func parseTestGraph(path string) (*channeldb.ChannelGraph, func(), aliasMap, err
 		}
 
 		edgePolicy := &channeldb.ChannelEdgePolicy{
+			Signature:                 testSig,
 			ChannelID:                 edge.ChannelID,
 			LastUpdate:                time.Now(),
 			TimeLockDelta:             edge.Expiry,