Pushed a new ElasticSearch processor

[Mike Thomsen <mi...@gmail.com>]

https://github.com/apache/nifi/pull/2113

JsonQueryElasticsearch5

- Uses the ElasticSearch 5 REST client (they have two Java clients, I used
the REST one so we can throw pure JSON for everything in there).
- Should support X-Pack based on using their samples of how to do SSL and
BasicAuth with the REST client.
- Supports EL in Query, Index and Type fields.
- Designed to let you copy and paste a full JSON query from Kibana into its
Query field and run it.
- Can run aggregations and send them down a separate relationship for
aggregations.

The only thing it doesn't support is pagination/scroll queries mainly
because when I wrote this we had no use case for that versus running
aggregations.

It should have a fighting chance of supporting ES 6 and 7 because it
doesn't require you to specify a type and types are going away in ES 7
apparently.