Reorient the E&A ESQL/query languages overview pages

[leemthompo]

• Assess and improve navigation paths between narrative and reference docs
• Update Get started and subsequent pages in narrative content to improve the learning journey about:
  • the language itself:
  • each interface that supports the language (incl. Kibana features)
• Improve https://www.elastic.co/docs/explore-analyze/query-filter/languages to better highlight the various contexts where some languages are used in and serve as a better entry point to orientate users landing on that page.

References:

#2658
elastic/elasticsearch#133301

[florent-leborgne]

Created #2858 to improve the Query DSL page in Explore & Analyze and bring different value than what's already in the reference docs