add(core): show less entries in download

static/index.html

@@ -109,6 +109,11 @@
           </thead>
           <tbody></tbody>
         </table>
+        <div class="bar" id="import-pager" hidden>
+          <button id="import-prev" class="secondary">← Zurück</button>
+          <span id="import-page-info" class="muted"></span>
+          <button id="import-next" class="secondary">Weiter →</button>
+        </div>
         <div class="bar">
           <button id="import-btn" hidden>Ausgewählte importieren</button>
         </div>