some modularizing and refactoring

modules/nixos/system/devpkgs/default.nix

@@ -0,0 +1,50 @@
+{
+  pkgs,
+  lib,
+  config,
+  ...
+}: let
+  inherit (lib) mkIf mkOption types;
+  cfg = config.nixos.system.devpkgs;
+in {
+  options = {
+    nixos.system.devpkgs = {
+      enable = mkOption {
+        type = types.bool;
+        default = false;
+        description = "Enable various packages for development";
+      };
+    };
+  };
+
+  config = mkIf cfg.enable {
+    environment.systemPackages = with pkgs; [
+      # Language servers, utilities, and tools
+      gcc
+      rust-analyzer
+      lua-language-server
+      nixd
+      php
+      # php84Packages.php-cs-fixer
+      phpactor
+      python312Packages.python-lsp-server
+      bash-language-server
+      nil
+      nodePackages.vscode-langservers-extracted
+      clang-tools
+      marksman
+      pyright
+      nodePackages_latest.intelephense
+
+      # Formatters
+      alejandra
+      stylua
+      nodePackages_latest.fixjson
+      nodePackages_latest.sql-formatter
+      prettierd
+      shfmt
+      luaformatter
+      black
+    ];
+  };
+}