Cannot update database schemes in translate.lizard

Originally created by @emmapeel on #15308 (Redmine)

We need to allow the user weblate to write new migration fixtures to

/usr/local/share/weblate/weblate/trans/migrations/

In order to create such fixtures and allow the updating of the database.

This is needed before the SponsorL work starts.

Parent Task: tails/sysadmin#11759