Link to downloadable report for org usage

Link is sticky so that it is easy to spot even when
an org has many services.

app/templates/views/organisations/organisation/index.html

@@ -112,4 +112,10 @@
     <div class="keyline-block govuk-!-margin-top-2"></div>
   {% endif %}
 
+  <div class="js-stick-at-bottom-when-scrolling">
+    <p class="bottom-gutter">
+      <a href="{{ download_link }}" download="download" class="govuk-link govuk-link--no-visited-state govuk-!-font-weight-bold">Download this report</a>
+    </p>
+  </div>
+
 {% endblock %}