**Reason**
T211428#4857070
**To-do list**
- [x] Archive documentation on `mediawiki.org` (https://www.mediawiki.org/wiki/Extension:UploadLocal).
- [ ] Archive Wikidata item associated with documentation page (https://www.wikidata.org/wiki/Q21678955).
- Configuration/tests/integrations/etc.
-- [x] Remove from `mediawiki/extensions` (along with in `.gitmodules`).
-- [x] Remove tests in [[ https://gerrit.wikimedia.org/g/integration/config | `integration/config` ]] (`zuul/layout.yaml`).
- Repositories
-- [x] Remove from #translatewiki.net
-- [x] Empty repository and add an ARCHIVED file.
-- [x] Archive the diffusion repository for the extension.
-- [x] Mark the repository read-only in Gerrit (https://gerrit.wikimedia.org/g/mediawiki/extensions/UploadLocal).
-- [ ] Delete the GitHub mirror (https://github.com/wikimedia/mediawiki-extensions-UploadLocal).