This changed introduces 4 new parameters to be able to use an existing
elasticsearch service for central logging.

* elasticsearch_address - address of elasticsearch server
* elasticsearch_protocol - protocol (HTTP/HTTPS) used by elasticsearch server
* enable_elasticsearch - deploy elasticsearch container
* enable_kibana - deploy kibana container

Closes-bug: #1584861

Change-Id: Ia1ff9ae8b6d9929c3826da02693d1e2fc9ea2522