Add Overpass QL

[k-yle]

Closes #6311

Description

See extensive description in issue #6311

Checklist:

• I am adding a new language.
  • The extension of the new language is used in hundreds of repositories on GitHub.com.
    • Search results for each extension:
      • https://github.com/search?type=code&q=NOT+is%3Afork+path%3A*.overpassql - 612 files from 200+ repositories
      • see extensive research and work by @FloEdelmann - link to github project
  • I have included a real-world usage sample for all extensions added in this PR:
    • Sample source(s):
      • written by me based on the documentation
    • Sample license(s):
      • created by me, happy to license it under the same license as this repository
  • I have included a syntax highlighting grammar: tqdv/vscodium-overpassql-syntax
  • I have added a color
    • Hex value: ${\color{#cce2aa} \blacksquare}$ #cce2aa
    • Rationale: Sampled from the OpenStreetMap logo
  • I have updated the heuristics to distinguish my language from others using the same extension.

[FloEdelmann]

Thanks for the ping and thanks a lot for the PR! This was on my todo list for way to long.

When/if this is merged, it might be worth creating a short blog entry for WeeklyOSM to mention that .overpassql files now have syntax highlighting on GitHub, and also linking @tqdv's VS Code extension.