Improve folder structure

nix/lib/default.nix

@@ -0,0 +1,12 @@
+{ config, lib, ... }:
+
+with lib; rec {
+
+  pkgsImport = pkgs:
+    import pkgs {
+      config = config.nixpkgs.config;
+      overlays = config.nixpkgs.overlays;
+      system = config.nixpkgs.system;
+    };
+
+}