Configure addons in Weblate

Originally created by @Anonymous on #15409 (Redmine)

https://docs.weblate.org/en/latest/admin/addons.html#cleanup-translation-files

I’d like us to configure these plugins:

- cleanup translation files

- update po files to match pot (might not be necessary)
- customize gettext (set line wrap to 79 chars)

available in weblate 2.19.

Feature Branch: emmapeel:feature/15409-addons_weblate

Parent Task: #11759 (closed)

Related issues

• Blocked by #15274 (closed)