A tutorial showing how to start elasticsearch, logstash and kibana using flocker - 562

Ok. I think this is ready for a review.

 * We're linking to @tomprince 's test images at the moment, but those links can be updated when https://github.com/ClusterHQ/docker-images/pull/7 gets merged.
 * This is another rather repetitive "tutorial" document, but I guess that can be improved later in #634

Fixes #562