Support new authentication configuration format starting EnterpriseSearch 8.x

[thbkrkr]

Resolves #3725.

[barkbay]

I did a test with *:8.0.0-SNAPSHOT docker images, I have the following errors in the logs:

[2020-09-09T13:45:29.604+00:00][1][2422][worker][ERROR]: Error in processing loop; Sleeping for 4s before trying again
Elasticsearch::Transport::Transport::Errors::BadRequest ([400] {"error":{"root_cause":[{"type":"illegal_argument_exception","reason":"invalid parameter [size], use [max_docs] instead"}],"type":"illegal_argument_exception","reason":"invalid parameter [size], use [max_docs] instead"},"status":400})
	/usr/share/enterprise-search/lib/war/gems/gems/elasticsearch-transport-7.0.0/lib/elasticsearch/transport/transport/base.rb:218:in `__raise_transport_error'
	/usr/share/enterprise-search/lib/war/gems/gems/elasticsearch-transport-7.0.0/lib/elasticsearch/transport/transport/base.rb:338:in `perform_request'
	/usr/share/enterprise-search/lib/war/gems/gems/elasticsearch-transport-7.0.0/lib/elasticsearch/transport/transport/http/faraday.rb:37:in `perform_request'
	/usr/share/enterprise-search/lib/war/gems/gems/elasticsearch-transport-7.0.0/lib/elasticsearch/transport/client.rb:160:in `perform_request'
	/usr/share/enterprise-search/lib/war/gems/gems/elasticsearch-api-7.0.0/lib/elasticsearch/api/actions/update_by_query.rb:88:in `update_by_query'
	/usr/share/enterprise-search/lib/war/vendor/esqueues-me/lib/esqueues_me/worker.rb:123:in `claim_work'
	/usr/share/enterprise-search/lib/war/vendor/esqueues-me/lib/esqueues_me/worker.rb:98:in `work'
	/usr/share/enterprise-search/lib/war/vendor/esqueues-me/lib/esqueues_me/worker.rb:69:in `block in start_processing_loop!'
	org/jruby/RubyKernel.java:1446:in `loop'
	/usr/share/enterprise-search/lib/war/vendor/esqueues-me/lib/esqueues_me/worker.rb:63:in `start_processing_loop!'
	/usr/share/enterprise-search/lib/war/vendor/esqueues-me/lib/esqueues_me.rb:106:in `start!'
	/usr/share/enterprise-search/lib/war/shared_togo/lib/shared_togo.class:732:in `start_esqueues_me!'
	/usr/share/enterprise-search/lib/war/shared_togo/lib/shared_togo.class:145:in `start_worker!'
	<script>:1:in `<main>'

But it does not seem related to an authentication problem, so LGTM.

[thbkrkr]

I did not see that but it might be worth contacting the ENT team about this if we know how to reproduce it. It seems related to elastic/elasticsearch#43373. The log indicates elasticsearch-api-7.0.0 is still in use.