lang/org: general refactor; split init into hooks

lang/org's initialization process is now split up into hooks on
org-load-hook. This approach is cleaner and easier to customize. I also
removed the escape binding in org-agenda-mode-map, as the popup system
makes it redundant.

modules/lang/org/+present.el

@@ -1,5 +1,7 @@
 ;;; lang/org/+present.el -*- lexical-binding: t; -*-
 
+(add-hook 'org-load-hook #'+org|init-present)
+
 (defvar +org-present-text-scale 7
   "The `text-scale-amount' for `org-tree-slide-mode'.")
 
@@ -43,7 +45,7 @@
 ;; Bootstrap
 ;;
 
-(after! org
+(defun +org|init-present ()
   (require 'ox-reveal)
   (map! :map org-mode-map "<f8>" #'+org-present/start))