Add wait_for check for ES to become available.
Add wait_for check for ES to become available.

ES 5.x series requires substantially more resources than 2.4
series.  As such underpowered VM or hosts may need more time
to wait for elasticsearch to start.

I am putting this check in hoping that it will fix potential
chain-dependency issues with services relying on other services
to start in a timely fashion.

related-to: https://github.com/sadsfae/ansible-elk/issues/26

sadsfae/ansible-elk