add standalone clightning-rest service

- Rename `services.rtl.cl-rest` to `services.clightning-rest`.
  `clightning-rest` is generally useful for connecting external REST clients
  to clightning.

- Add a dedicated network namespace in netns-isolation.

- Add nodeinfo entry.

- Add datadir (which contains REST auth data) to backups.

modules/versioning.nix

@@ -213,6 +213,17 @@ let
         See also: https://github.com/dgarage/NBXplorer/blob/master/docs/Postgres-Migration.md
       '';
     }
+    {
+      version = "0.0.70";
+      condition = config.services.clightning-rest.enable;
+      message = ''
+        The `cl-rest` service has been renamed to `clightning-rest`.
+        and is now available as a standalone service (`services.clightning-rest`).
+        Its data dir has moved to `${config.services.clightning-rest.dataDir}`,
+        and the service now runs under the clightning user and group.
+        The data dir migration happens automatically after deploying.
+      '';
+    }
   ];
 
   mkOnionServiceChange = service: {