Elasticsearch v7.0 changed the behavior of max concurrent shard
requests and the default to 5. v5.6 and before 7.0 the default
is 256. This adds some additional behavior given certain
version is selected when configure the datasource to set
default max concurrent shard requests.
Changing from a version pre-v7.0+ to v7.0+ sets max
concurrent shard requests to 5.
Changing from a version v7.0+ to a pre-v7.0 sets max
concurrent shard requests to 256.
Fixes#17454
Adds a new version option 7.0+ (70 internally).
Version 7.0+ doesn't include document types in index mappings
so support for handling this have been added.
Version 7.0+ returns number of hits in a different way so
support for handling this have been added.
Version 7.0+ doesn't support sending
max_concurrent_shard_requests in multisearch header so
support for sending this in query string have been added.
Update elastic6 docker block and dashboards (devenv) to use
6.7.1 images, filebeat index name is now filebeat-YYYY.MM.DD
and dashboard include correct tags and links.
Add elastic7 docker block and provisioning (devenv).
Updates documentation regarding new version.
Closes#15622
