refactor: move nix config to a module

nixosModules/nix-config.nix

@@ -0,0 +1,43 @@
+{
+  config,
+  lib,
+  pkgs,
+  ...
+}:
+let
+  moduleName = "nix-config";
+  cfg = config."${moduleName}";
+in
+{
+  options = {
+    "${moduleName}".enable = lib.mkEnableOption "Enable ${moduleName}.";
+  };
+
+  config = lib.mkIf cfg.enable {
+    system.stateVersion = "24.11";
+
+    nixpkgs.config.allowUnfree = true;
+
+    nix.settings = {
+      experimental-features = [
+        "nix-command"
+        "flakes"
+        "pipe-operators"
+      ];
+
+      trusted-users = [ "@wheel" ];
+
+      # Add binary caches to avoid having to compile them
+      substituters = [
+        "https://cache.nixos.org"
+        "https://nix-community.cachix.org"
+      ];
+      trusted-public-keys = [
+        "cache.nixos.org-1:6NCHdD59X431o0gWypbMrAURkbJ16ZPMQFGspcDShjY="
+        "nix-community.cachix.org-1:mB9FSh9qf2dCimDSUo8Zy7bkq5CX+/rkCWyvRCYg3Fs="
+      ];
+    };
+
+    programs.nix-ld.enable = true;
+  };
+}