further modularization + systemd template

modules/dev/sh.nix

@@ -0,0 +1,10 @@
+{ config, lib, pkgs, ... }: {
+  options.my.dev.sh.enable = lib.mkEnableOption "enable";
+  config = lib.mkIf config.my.dev.sh.enable {
+    users.users.jawz.packages = (with pkgs; [
+      bashdb # autocomplete
+      shellcheck # linting
+      shfmt # a shell parser and formatter
+    ]) ++ (with pkgs.nodePackages; [ bash-language-server ]);
+  };
+}