Move out datengartens into their own section

- /datengarten/index.html returns a blog-like list
- /datengarten/index.ics returns a VCALENDAR
- /datengarten/index.xml returns a schedule.xml-style view

No more pretty rendering includes in the content pages,
some more cleanup in the front matter

layouts/datengarten/single.html

@@ -0,0 +1,59 @@
+{{ define "main" }}
+<div class="container" role="main">
+  <div class="row">
+    <div class="col-lg-8 col-lg-offset-2 col-md-10 col-md-offset-1">
+      <article role="main" class="blog-post">
+	{{ partial "talk-infobox" . }}
+        {{ .Content }}
+
+        {{ if .Params.tags }}
+          <div class="blog-tags">
+            {{ range .Params.tags }}
+              <a href="{{ $.Site.LanguagePrefix | absURL }}/tags/{{ . | urlize }}/">{{ . }}</a>&nbsp;
+            {{ end }}
+          </div>
+        {{ end }}
+
+        {{ if .Site.Params.socialShare }}
+            <hr/>
+            <section id="social-share">
+              <ul class="list-inline footer-links">
+                {{ partial "share-links" . }}
+              </ul>
+            </section>
+        {{ end }}
+      </article>
+
+      {{ if ne .Type "page" }}
+        <ul class="pager blog-pager">
+          {{ if .PrevInSection }}
+            <li class="previous">
+              <a href="{{ .PrevInSection.Permalink }}" data-toggle="tooltip" data-placement="top" title="{{ .PrevInSection.Title }}">&larr; {{ i18n "previousPost" }}</a>
+            </li>
+          {{ end }}
+          {{ if .NextInSection }}
+            <li class="next">
+              <a href="{{ .NextInSection.Permalink }}" data-toggle="tooltip" data-placement="top" title="{{ .NextInSection.Title }}">{{ i18n "nextPost" }} &rarr;</a>
+            </li>
+          {{ end }}
+        </ul>
+      {{ end }}
+
+
+      {{ if (.Params.comments) | or (and (or (not (isset .Params "comments")) (eq .Params.comments nil)) (and .Site.Params.comments (ne .Type "page"))) }}
+        {{ if .Site.DisqusShortname }}
+          <div class="disqus-comments">
+            {{ template "_internal/disqus.html" . }}
+          </div>
+        {{ end }}
+        {{ if .Site.Params.staticman }}
+          <div class="staticman-comments">
+            {{ partial "staticman-comments.html" . }}
+          </div>
+        {{ end }}
+      {{ end }}
+
+    </div>
+  </div>
+</div>
+{{ end }}