Support long scroll id for clear scroll

[saurtm12]

• put the scroll id into the body as new es api instead of marking it in the url

Fix the issue with long scroll id:

Configure elastic with a lot of data and I want to use elasticsearch stream input, then it doesnt work with scrolling and have this error:
error_class=Elasticsearch::Transport::Transport::Errors::BadRequest error="[400] {"error":{"root_cause":[{"type":"too_long_frame_exception","reason":"An HTTP line is larger than 4096 bytes."}],"type":"too_long_frame_exception","reason":"An HTTP line is larger than 4096 bytes."},"status":400}"","worker_id":0} #<Thread:0x000000000411a798@in_elasticsearch_thread_1000 /opt/td-agent/lib/ruby/gems/2.7.0/gems/fluentd-1.14.6/lib/fluent/plugin_helper/thread.rb:70 run> terminated with exception (report_on_exception is true):
DESCRIPTION HERE

(check all that apply)

• tests added
• tests passing
• [ x] README updated (if needed)
• [ x] README Table of Contents updated (if needed)
• [ x] History.md and version in gemspec are untouched
• [ x] backward compatible
• feature works in elasticsearch_dynamic (not required but recommended)

[cosmo0920]

Superseded by #1039