Reason
The Geoshapes service was never deployed, and yet its code sits around confusing people e.g. in T364779. Let's just empty the repo and archive it.

To-do list

• This task
  • Add maintainers of that service as subscribers to this task (if they have no apparent Phabricator account, notify them on-wiki or via email if possible and note it here).
  • Add Phabricator project Maps (Geoshapes) as a tag for this task
• On-wiki documentation
  • Archive documentation on mediawiki.org
• Configuration/tests/integrations/etc.
  • Remove tests in integration/config (zuul/layout.yaml).
• Repositories
  • Empty repository, leaving only the README indicating the repo is archived, and referring to this task by URL.
  • Mark the repository read-only in Gerrit (also edit description to prepend "[ARCHIVED T418372]", remove all access lists and reparent on All-Archived-Projects): https://gerrit.wikimedia.org/g/mediawiki/services/geoshapes
  • Deactivate the Diffusion repository for the extension/skin: https://phabricator.wikimedia.org/diffusion/MSGE/
  • Delete the GitHub mirror: https://github.com/wikimedia/mediawiki-services-geoshapes