add explanation text + reformat

templates/admin/user/view.html.tera

@@ -391,6 +391,8 @@
                         <ul class="list-disc ms-4">
                             {% for activity in activities %}
                                 <li>{{ activity.created_at | date(format="%d. %m. %Y") }}: {{ activity.text }}</li>
+                            {% else %}
+                                <li>Noch keine Aktivität... Stay tuned 😆</li>
                             {% endfor %}
                         </ul>
                     </div>