#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

templates/report/unavailable.html

@@ -0,0 +1,14 @@
+{% extends 'public_base.html' %}
+{% load i18n %}
+
+{% block body %}
+    <div class="jumbotron">
+        <h1 class="display-4">{% trans 'Unrecorded data' %}</h1>
+        <hr>
+        <p class="lead">
+            {% blocktrans %}
+            The data you want to see is not recorded and might still be work in progress. Please come back another time.
+            {% endblocktrans %}
+        </p>
+    </div>
+{% endblock %}