Monitoring of Elasticsearch requests

[scampi]

It would be nice to have a page, akin to the status page, that informs on the performance of the queries run in Kibana (visualizations, searches, aggregations, ...).

Some use cases:

• we could see what query misbehave and investigate why. This page could maybe suggests a better way to write the query, or a better definition for a visualization, ...
• we could find why a dashboard loads slowly, and pin-point which visualization is the cause.

[cjcenizal]

Somewhat related: we've added a new Inspector tool which you can use to inspect each visualization in a dashboard and examine the request(s) it's made and how long they took, which can help you figure out which visualizations may be slowing down a dashboard.

[tylersmalley]

This seems to be resolved. We can log all ES queries, and you can use search sessions to view the queries in the UI.