chore: organise modules

Organise modules in a significantly better way with categories.

modules/nix/darwin.nix

@@ -0,0 +1,33 @@
+{ config, lib, pkgs, ... }:
+
+{
+  system.activationScripts.applications.text = let
+    appsSrc = config.system.build.applications + /Applications;
+    baseDir = "/Applications/Nix Apps";
+  in
+    pkgs.lib.mkForce ''
+      echo 'Setting up /Applications/Nix Apps...' >&2
+      appsSrc="${appsSrc}"
+      if [ -d "$appsSrc" ]; then
+        baseDir="${baseDir}"
+        rsyncFlags=(
+          --archive
+          --checksum
+          --chmod=-w
+          --copy-unsafe-links
+          --delete
+          --no-group
+          --no-owner
+        )
+        $DRY_RUN_CMD mkdir -p "$baseDir"
+        $DRY_RUN_CMD ${lib.getBin pkgs.rsync}/bin/rsync \
+          ''${VERBOSE_ARG:+-v} "''${rsyncFlags[@]}" "$appsSrc/" "$baseDir"
+      fi
+    '';
+
+  # use determinate nix
+  nix.enable = false;
+
+  # changing this might break
+  system.stateVersion = 5;
+}

modules/nix/linux.nix

@@ -0,0 +1,9 @@
+{ config, lib, pkgs, ... }:
+
+{
+  # Nix Configuration
+  nixpkgs.config.allowUnfree = true;
+
+  # Enable nix-command and flakes
+  nix.settings.experimental-features = [ "nix-command" "flakes" ];
+}