#67 Parcel error fix

* adds workaround in case of received WFS exception -> routine waits 1 second and tries to rerun for another time. If this does fail as well, the routine will end without a result
* adds mailto shortcut to contact button in footer for a quick fix

templates/footer.html

@@ -9,7 +9,7 @@
                 <a href="{% url 'home' %}">{% trans 'Impressum' %}</a>
             </span>
             <span class="col-sm-auto footer-link">
-                <a href="{% url 'home' %}">{% trans 'Contact' %}</a>
+                <a href="mailto:{{CONTACT_MAIL}}">{% trans 'Contact' %}</a>
             </span>
         </div>
     </div>