Progress rewrite further

modules/nixos/core/nix.nix

@@ -0,0 +1,19 @@
+{ lib, ... }:
+
+{
+  nix = {
+    settings = {
+      auto-optimise-store = true;
+      use-xdg-base-directories = true;
+      trusted-users = [ "@wheel" ];
+      allowed-users = [ "@wheel" ];
+    };
+  };
+
+  nixpkgs = {
+    config = {
+      allowUnfree = true;
+    };
+    hostPlatform = lib.mkDefault "x86_64-linux";
+  };
+}