Insert scheduled downtime infos from cloud calendar

Change-Id: I8e4524126c08c4b89298e29b4c17588ef3997b71
diff --git a/templates/en/about.html.ep b/templates/en/about.html.ep
index fd2fb7e..8492134 100644
--- a/templates/en/about.html.ep
+++ b/templates/en/about.html.ep
@@ -16,4 +16,8 @@
     Things can change unannounced at any time and even a complete breakdown over a longer period of time cannot be excluded with certainty.
     If you would like to use DeReKoVecs for your own research in the longer term, please contact us.
 </p>
+<h3>Scheduled downtimes</h3>
+<dl id="downtimes">
+    <dt></dt><dd>–</dd>
+</dl>
 </html>