[Reporting] Use Search Sessions to speed up capture time

[tsullivan]

With the Search Sessions feature in Kibana, search results can be preloaded in Elasticsearch and viewed later in a Kibana dashboard or other application.

Reporting should utilize Search Sessions so that when a request to generate a report is triggered, the it creates a search session in the background. Once the session has complete status, then Reporting loads the URL and views the application which loads the search session.

This would improve Reporting performance because it removes the latency from the headless browser's requests. The headless browser wouldn't need to stay open as long, which lowers the CPU and RAM utilization.

Thanks to @streamich for the idea.

[elasticmachine]

Pinging @elastic/kibana-app-services (Team:AppServices)

[elasticmachine]

Pinging @elastic/kibana-reporting-services (Team:Reporting Services)

[ppisljar]

Thank you for contributing to this issue, however, we are closing this issue due to inactivity as part of a backlog grooming effort. If you believe this feature/bug should still be considered, please reopen with a comment.