When validating the Elasticsearch configuration, we'd check if the

elasticsearch module was available and was of a compatible version. If

either failed, we'd display a generic error about ensuring you have a

compatible elasticsearch.
This change updates validation to show an error specific to each case.

Both include the list of packages to install for Elasticsearch support.
Unit tests have been added to ensure validation works and to track any

changes to our list of compatible versions.

Manually tested this without elasticsearch installed, and with an

incompatible version.
Unit tests passed.