Big re-write :)

I reordered the code in a more clean an organized way. Also this improves a lot
the emacs startup time again, bucause after some updates it becomes a bit slow
with the old configuration, so i did it again in a new way.

configs/lang-rust.el

@@ -10,8 +10,6 @@
 ;;; Code:
 
 (use-package rust-mode
-  :defer t
-  :ensure t
   :init
   (setq rust-mode-treesitter-derive t)
   :config