add support for ElasticSearch

[afeld]

Doesn't seem that ElasticSearch has a canonical REPL, though there is one out there:

https://github.com/mkocikowski/elsec

Alternatively, we can just print out the curl command to use.

https://www.elastic.co/guide/en/elasticsearch/guide/current/_talking_to_elasticsearch.html#_restful_api_with_json_over_http

I know @yozlet was using the cf-service-proxy on College Scorecard...this might be a nice alternative for them.