Revert "Do not enable company completion in Org Mode buffers by default"

This reverts commit 2622b048b6.

The main annoyance has been completion in org source blocks, and this has been
disabled now.  Additionally, `company-complete` only seems to work when
company-mode is enabled.  So let's enable it again and see how far we get.

init.el

@@ -850,6 +850,9 @@
                                            (emacs-lisp . t))))
   :config (progn
 
+            ;; Allow company completion in Org Mode buffers
+            (add-hook 'org-mode-hook 'company-mode)
+
             ;; Reset checkboxes if the RESET_CHECK_BOXES property is set
             (add-hook 'org-after-todo-state-change-hook 'org-reset-checkbox-state-maybe)