Support Elasticsearch 8 as an output in RHOCP 4

Issue

• Needed to send logs to Elasticsearch 8
• Not able to send logs from OCP Logging stack to Elasticsearch 8

• Failing to deliver logs to Elasticsearch 8 with the error contains an unknown parameter [_type]

  $ oc logs <collector> -n openshift-logging
  2022-04-25 06:24:05 +0000 [warn]: [elasticsearch8] failed to flush the buffer. retry_time=36 next_retry_seconds=2022-04-25 06:25:02 +0000 chunk="5dd7459d6d36c1e0875d29c091e3947f" error_class=Fluent::Plugin::ElasticsearchOutput::RecoverableRequestFailure error="could not push logs to Elasticsearch cluster ({:host=>\"elasticsearch8.example.com\", :port=>9200, :scheme=>\"https\", :user=>\"user\", :password=>\"obfuscated\"}): [400] {\"error\":{\"root_cause\":[{\"type\":\"illegal_argument_exception\",\"reason\":\"Action/metadata line [1] contains an unknown parameter [_type]\"}],\"type\":\"illegal_argument_exception\",\"reason\":\"Action/metadata line [1] contains an unknown parameter [_type]\"},\"status\":400}"