Search Templates for Elasticsearch Interpreter

The current version of ElasticSearch interpreter doesn't allow to execute search queries against Search Templates of Elastic Search (see: https://www.elastic.co/guide/en/elasticsearch/reference/current/search-template.html ).

This can work very similar to search part, where full JSON must be passed.

If it will be assigned, I can provide the assignee our code how we generalized Search Templates calling from Java (but using the newest Java Client). So it can be easier to imagine what else should be modified.