nix: remove module export in flake

nix/nixosModules/default.nix

@@ -1,33 +0,0 @@
-{self, ...} @ inputs: let
-  inherit
-    (self.lib)
-    modulesFromDir
-    mergeAttrsWith
-    ;
-
-  inherit (inputs.nixpkgs) lib;
-
-  # generic modules that can be enabled on all devices
-  common =
-    mergeAttrsWith (x: y: {imports = [x y];})
-    (modulesFromDir ./common)
-    {
-      agenix = inputs.agenix.nixosModules.default;
-      url-eater = inputs.url-eater.nixosModules.default;
-    };
-
-  # extra opt-in configurations
-  extra = modulesFromDir ./extra;
-
-  # per host configuration
-  named =
-    lib.mapAttrs'
-    (name: lib.nameValuePair ("named-" + name))
-    (modulesFromDir ./named);
-in
-  lib.mergeAttrsList [
-    {commonModules.imports = lib.attrValues common;}
-    common
-    extra
-    named
-  ]