Add a first version of a mobile friendly UI

Although not perfect and with many flaws, this should still allow far
easier navigation on mobile devices.

core/templates/core/delete_confirm.jinja

@@ -4,6 +4,12 @@
 {% trans %}Delete confirmation{% endtrans %}
 {% endblock %}
 
+{% block info_boxes %}
+{% endblock %}
+
+{% block nav %}
+{% endblock %}
+
 {% block content %}
 <h2>{% trans %}Delete confirmation{% endtrans %}</h2>
 <form action="" method="post">{% csrf_token %}