add total file size stat for ranking page

views/ranking.html

@@ -82,6 +82,7 @@
               <tr><td>{{ t('ranking.stat_nsfl') }}</td><td>{{ stats.nsfl }}</td></tr>
             @endif
             <tr><td>{{ t('ranking.stat_deleted') }}</td><td>{{ stats.deleted }}</td></tr>
+            <tr><td>{{ t('ranking.stat_disk_usage') }}</td><td>{{ diskSize }}</td></tr>
           </tbody>
         </table>
       </div>