Requires a reset + reindex of everything (well, that's the easiest way to
get things indexed properly again), which will loose us the Cloud stats.
Before doing this, export those to MongDB and upgrade the statscollector
to the version that I'll be committing soon.
We can then remove X-Pack and control ElasticSearch's memory usage.
This also gives us the opportunity to let Kibana do its optimization when
we build the image, rather than every time the container is recreated.
