Make configuration of ElasticSearch more dynamic

[leifmadsen]

Currently the usage of the lineinfile module just makes the configuration of ES somewhat awkward and more difficult than it really needs to be.

A better approach would be to use a template.

[leifmadsen]

I've added a PR for this issue, but it's not yet complete as I have to update the documentation, and go through the other open PRs to mark them as deprecated in favour of this one (assuming the approach is accepted).

[davidak]

The PR is merged so this should be closed.

[geerlingguy]

@davidak - Great, thanks for reminding me!