Official elasticsearch image from docker hub soon to be deprecated

[kierenevans]

https://hub.docker.com/_/elasticsearch/ says to update to use the images provided by elastic.co instead, referring to: https://www.elastic.co/guide/en/elasticsearch/reference/current/docker.html

[kierenevans]

The docker hub version is debian based, the elastic.co images are centos based.

[kierenevans]

Not sure of the upgrade path for 5.5, 2.4 and 1.7 as it would be an OS change that may break downstream images