Adds breadcrumbs and navigation, moves QR code to its own page.

app/templates/breadcrumbs.html

@@ -0,0 +1,15 @@
+<div class="breadcrumbs">
+<nav class="breadcrumb" aria-label="breadcrumbs">
+{% set ns = namespace(crumb_path=request.url_root[:-1])%}
+{# We use a namespace since jinja 2 variables cannot persist outside loops
+    The crumb_path var dynamically constructs urls for each breadcrumb based on request.path (removing the trailing slash),
+    We need to do this for the file viewer, as it can have many nested directories, but works for all other pages. #}
+  <ul>
+      {% set breadcrumbs = request.path[1:].split('/') %} {# request.path starts with / #}
+      {% for crumb in breadcrumbs %}
+        {% set ns.crumb_path = ns.crumb_path + "/" +crumb %}
+        <li><a href="{{ ns.crumb_path }}">{{crumb}}</a></li>
+      {% endfor %}
+  </ul>
+</nav>
+</div>