feat: split config more

modules/nixos/usecases/3d-printing.nix

@@ -0,0 +1,27 @@
+{
+  config,
+  lib,
+  pkgs,
+  ...
+}:
+
+with lib;
+
+let
+  cfg = config.usecases."3d-printing";
+in
+{
+  options.usecases."3d-printing" = {
+    enable = mkEnableOption "Enable 3d printing stuff";
+  };
+
+  config = mkIf cfg.enable {
+    environment.systemPackages = with pkgs; [
+      lpc21isp
+      dfu-util
+      cura
+      openscad-unstable
+      freecad
+    ];
+  };
+}