added website code for containerd.io

Signed-off-by: Patrick Chanezon <patlist@chanezon.com>

docs/_layouts/default.html

@@ -0,0 +1,15 @@
+{% include header.html %}
+
+<div class="navbar white">
+  <div class="name"><a href="/">containerd<span class="org">By Docker</span></a></div>
+  <div class="actions">
+      {% include links.html %}
+  </div>
+</div>
+<div class="content">
+  <div class="wrapper-details">
+    {{ content }}
+  </div>
+</div>
+
+{% include footer.html %}