nixUtils: migrated multiple packages to separate file

modules/nixos/nixUtils.nix

@@ -1,12 +1,9 @@
 {
-  config,
-  pkgs,
   pkgs-unstable,
-  libs,
   inputs,
   ...
 }: {
-# Garbage collector of generations
+  # Garbage collector of generations
   nix.gc = {
     automatic = true;
     dates = "weekly";
@@ -15,4 +12,23 @@
   # nixpkgs-review crashed my laptop multiple times.
   nix.settings.max-jobs = 2;
   nix.settings.cores = 2;
+
+  #manix is unhappy without this
+  nix.nixPath = [
+    "nixpkgs=${inputs.nixpkgs.outPath}"
+    "home-manager=${inputs.home-manager.outPath}"
+  ];
+
+  #adds nixos experimental features:
+  nix.settings.experimental-features = ["nix-command" "flakes"];
+
+  environment.systemPackages = with pkgs-unstable; [
+  nixpkgs-review
+  nixfmt-tree
+  treefmt
+  nixd
+  manix
+  deadnix
+  alejandra
+  ];
 }