Refactor Explore&Analyze > Query languages section

## Issue

The query languages section under Explore & Analyze has a lot of duplicate content with its counterpart Query languages reference section. This issue is to gather all existing issues about sanitizing this, and making refocusing this section on how these query languages surface in Kibana.

## Goals

- Deduplicate content between reference documentation and Kibana usage documentation: Reference part about the language should be in the reference docs, conceptual part about where/how to use it specifically in Kibana should be in explore & analyze, with links to the reference section
- Create the missing content to have a section that is talking about how to use these languages in kibana in an unified way