json_lines and url format when body is batch

[VolunPotest]

Hello. I noticed that library don't have json_lines format - so i fix it.
Now format can support json_lines

Also i added new config: batch_url_format (bool)
When ienabled - you can forma url when you use batch body with format: json_lines and json_batch

[cla-checker-service]

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[kercdbh]

I too would really love to have that json_lines format mode in the logstash http output plugin

[Gleb-Gadyatskiy]

Please merge it to Logstash :)