Remove Zim wiki editing commands

I no longer use Zim (but even if i will, i probably won’t need these).

configuration.org

@@ -816,30 +816,6 @@ HTML.
   (func-region start end #'url-unhex-string))
 #+END_SRC
 
-** Utility functions for editing Zim wiki files
-
-#+BEGIN_SRC emacs-lisp
-(defun zim-timestamp ()
-  (with-temp-buffer
-    (insert (format-time-string "%Y-%m-%dT%H:%M:%S%z"))
-    (forward-char -2)
-    (insert ":")
-    (buffer-string)))
-
-(defun insert-zim-timestamp ()
-  (interactive)
-  (insert (zim-timestamp)))
-
-(defun insert-zim-header ()
-  (interactive)
-  (save-excursion
-    (goto-char (point-min))
-    (insert
-     (concat "Content-Type: text/x-zim-wiki\n"
-             "Wiki-Format: zim 0.4\n"
-             "Creation-Date: " (zim-timestamp) "\n\n"))))
-#+END_SRC
-
 ** Utility functions for EDiff
 :PROPERTIES:
 :SOURCE:   http://article.gmane.org/gmane.emacs.orgmode/75222