Migrate to new elasticsearch client

[matthewhanson]

elasticsearch.js package is being deprecated and replaced with the new client:
https://www.npmjs.com/package/@elastic/elasticsearch

Migration guide here:
https://www.elastic.co/guide/en/elasticsearch/client/javascript-api/current/breaking-changes.html

[matthewhanson]

updated to the latest version of the old elasticsearch.js.

The API is supposed to be the same, so this may be an easy replace.

[matthewhanson]

updated to the new elasticsearch client, which also resulted in having to replace http-aws-es with aws-es-connection to allow for AWS Elasticsearch connections.