Use Kibana API to import modules metadata

Today, to import the Kibana dashboard, metadata and Kibana settings for modules, we directly write to ES (to `.kibana` index). While this works, there is no guarantee we're persisting this info correctly, and there is no validation. Also, Kibana might change the schema/representation of this metadata.

Recently, Kibana has introduced an API which can be used to import dashboards and other objects. https://github.com/elastic/kibana/pull/10858 (this API will work in both 5.5 and 5.6 for Kibana)

This would introduce a dependency of Kibana in Logstash. We should add this setting when setting up modules.