#25 Public reports

* adds public report rendering for intervention model
* adds new routes for report
* adds new public_base.html and public_navbar.html
* adds lookup table for zoom levels for lanis link generating
* moves qr code generating into utils/generators.py

intervention/templates/intervention/detail/includes/controls.html

@@ -6,7 +6,7 @@
             LANIS
         </button>
     </a>
-    <a href="{% url 'home' %}" class="mr-2">
+    <a href="{% url 'intervention:report' obj.id %}" class="mr-2" target="_blank">
         <button class="btn btn-default" title="{% trans 'Public report' %}">
             {% fa5_icon 'file-alt' %}
         </button>