improve nodeinfo

- enable usage outside of secure-node.nix
- use json as the output format
- show ports
- also show local addresses, which is particularly useful when
  netns-isolation is enabled
- only show enabled services

modules/modules.nix

@@ -27,6 +27,7 @@ with lib;
     ./onion-addresses.nix
     ./onion-services.nix
     ./netns-isolation.nix
+    ./nodeinfo.nix
     ./backups.nix
   ];