build: Add script to fix strict-types

[provokateurin]

Summary

Only a test to see what happens.

Anna: How much do you want to break?
Kate: Yes!

Checklist

• Code is properly formatted
• Sign-off message is added to all commits
• Tests (unit, integration, api and/or acceptance) are included
• Screenshots before/after for front-end changes
• Documentation (manuals or wiki) has been updated or is not required
• Backports requested where applicable (ex: critical bugfixes)
  Signed-off-by: provokateurin kate@provokateurin.de

[nickvergessen]

Had a recent crossing:
nextcloud/files_accesscontrol#591
So at least should not be backported, so we have enough time to notice issues. 🙈
But corner-cases are the tripping point with those

[provokateurin]

Exactly what we thought as well, so we're doing individual fixes and backporting those and then we can hopefully turn this on later once everything we found is fixed.

[provokateurin]

Rector can do this as well