Clarify differences from incubator/elasticsearch

[calbach]

This release seems more "official": https://github.com/kubernetes/charts/tree/master/incubator/elasticsearch

I'm wondering if there are intentional design differences, or if it's just two independent implementations. At least one caveat to that incubator version I've found is that it's on Elastic 2.4 (https://github.com/kubernetes/charts/issues/1864).

[sagikazarmark]

As far as I can see the incubator version uses fabric8 cloud kubernetes plugin whereas the elastic setup this helm chart is based on does not.

Ultimately this question would better be asked in https://github.com/pires/kubernetes-elasticsearch-cluster as this helm chart is purely just a port of those k8s configurations.