Major optimization refactor, across the board

+ enable lexical-scope everywhere (lexical-binding = t): ~5-10% faster
  startup; ~5-20% general boost
+ reduce consing, function calls & garbage collection by preferring
  cl-loop & dolist over lambda closures (for mapc[ar], add-hook, and
  various cl-lib filter/map/reduce functions) -- where possible
+ prefer functions with dedicated opcodes, like assq (see byte-defop's
  in bytecomp.el for more)
+ prefer pcase & cond (faster) over cl-case
+ general refactor for code readability
+ ensure naming & style conventions are adhered to
+ appease byte-compiler by marking unused variables with underscore
+ defer minor mode activation to after-init, emacs-startup or
  window-setup hooks; a customization opportunity for users + ensures
  custom functionality won't interfere with startup.

modules/ui/doom/config.el

@@ -1,4 +1,4 @@
-;;; ui/doom/config.el
+;;; ui/doom/config.el -*- lexical-binding: t; -*-
 
 (defvar +doom-theme 'doom-one
   "The color theme to use.")
@@ -38,10 +38,10 @@
   (load-theme +doom-theme t)
 
   ;; blink mode-line on errors
-  (doom-themes-visual-bell-config)
+  (add-hook 'emacs-startup-hook #'doom-themes-visual-bell-config t)
 
   ;; Add file icons to doom-neotree
-  (doom-themes-neotree-config)
+  (add-hook 'emacs-startup-hook #'doom-themes-neotree-config t)
   (setq doom-neotree-enable-variable-pitch t
         doom-neotree-file-icons 'simple
         doom-neotree-line-spacing 2)