Do not export diary by default

This had been used to synchronize my calender with others, but since this
synchronization is not in use anymore, regular exports are unnecessary.
Furthermore, the export makes Emacs unresponsive sometimes, as the export does
not seem to be easily preemtable.

init.el

@@ -916,10 +916,6 @@
                           (mapcar #'timer--function timer-list))
               (run-with-timer 0 3600 #'org-clock-save))
 
-            (unless (memq #'db/export-diary
-                          (mapcar #'timer--function timer-idle-list))
-              (run-with-idle-timer 200 t #'db/export-diary))
-
             ;; Hack: The default implementation is too slow, because it is
             ;; parsing all properties of an entry by default.  Let’s simplify
             ;; this to only parse what we are looking for.  This makes tag