rpcserver+lnrpc: make graph node addresses consistent

This commit adds a []*lnrpc.NodeAddress typed node_addresses field
on the NodeUpdate message of SubscribeChannelGraph to mirror the
addresses field in the LightningNode message of DescribeGraph.

Fixes https://github.com/lightningnetwork/lnd/issues/4084

lnrpc/rpc.proto

@@ -2768,11 +2768,21 @@ message GraphTopologyUpdate {
     repeated ClosedChannelUpdate closed_chans = 3;
 }
 message NodeUpdate {
-    repeated string addresses = 1;
+    /*
+    Deprecated, use node_addresses.
+    */
+    repeated string addresses = 1 [deprecated = true];
+
     string identity_key = 2;
+
+    /*
+    Deprecated, use features.
+    */
     bytes global_features = 3 [deprecated = true];
+
     string alias = 4;
     string color = 5;
+    repeated NodeAddress node_addresses = 7;
 
     /*
     Features that the node has advertised in the init message, node

lnrpc/rpc.swagger.json

@@ -4675,14 +4675,16 @@
           "type": "array",
           "items": {
             "type": "string"
-          }
+          },
+          "description": "Deprecated, use node_addresses."
         },
         "identity_key": {
           "type": "string"
         },
         "global_features": {
           "type": "string",
-          "format": "byte"
+          "format": "byte",
+          "description": "Deprecated, use features."
         },
         "alias": {
           "type": "string"
@@ -4690,6 +4692,12 @@
         "color": {
           "type": "string"
         },
+        "node_addresses": {
+          "type": "array",
+          "items": {
+            "$ref": "#/definitions/lnrpcNodeAddress"
+          }
+        },
         "features": {
           "type": "object",
           "additionalProperties": {