merge esv6 support updates

[bharathkontham]

Merging updates in https://github.com/bharathkontham/loopback-connector-elastic-search for ElasticSearch v6 support.

Following features are added:

• Only Elasticsearch 6.x is supported, ES 5.x or older version may or may not work.
• Currently only one Index can be configured in one ES datasource of loopback (working on multiple indices configuration support) but we can use same datasource multiple loopback models.
• A keyword field "docType" is used to store model names which provides support to use same Mapping Type of a single index for storing multiple models. This is major change in connector as earlier version used different mapping types to store different loopback models.
• Nested objects querying (array of objects type in loopback), geo spatial queries and like, nlike are supported.

Sample query for nested objects and geo_spatial:

{ "where": { "and": [ { "address.geo": { "geo_shape": { "address.geo": { "shape": { "type": "circle", "coordinates": [ 78.38214860577659, 17.44064909837838 ], "radius": "1km" }, "relation": "within" } } } }, { "entity_properties.value": { "gt": 50 } } ] } }

entity_properties is a nested object and address is an object. address.geo has geo_shape data.

[slnode]

Can one of the admins verify this patch? To accept patch and trigger a build add comment ".ok\W+to\W+test."

[pulkitsinghal]

@bharathkontham reminder - publish the package under the name loopback-connector-esv6 on npmjs which is different from loopback-connector-es ... this will let the following 2 packages follow their own version control, for example:

• npm install loopback-connector-es@1.4.1
• npm install loopback-connector-esv6@1.0.0

[bharathkontham]

Published package https://www.npmjs.com/package/loopback-connector-esv6