title: Allow import/export functions for super users only
body: <p>I would like to allow the import/export functions for superusers only. How can this be achieved?</p>
  
  <p>I managed to hide the import/export buttons through custom css. But I also would like to disable the corresponding function calls:</p>
  
  <p><a href="http://localhost:9012/admin/persons/person/import/" rel="nofollow noreferrer">http://localhost:9012/admin/persons/person/import/</a>
  <a href="http://localhost:9012/admin/persons/person/export/" rel="nofollow noreferrer">http://localhost:9012/admin/persons/person/export/</a></p>