adapt generator modules from clan-core modules

see https://git.clan.lol/clan/clan-core/src/branch/main/clanServices

backends/on-machine.nix

@@ -145,13 +145,5 @@ in
       generate-vars
     ];
     system.build.generate-vars = generate-vars;
-
-    systemd.services.generate-vars = {
-       wantedBy = [ "multi-user.target" ];
-       after = [ "default.target" ];
-       description = "generate needed secrets";
-       path = [ generate-vars ];
-       serviceConfig.ExecStart = "${generate-vars}/bin/generate-vars";
-    };
   };
 }