Make scaffold generators use emptyAsUndefined

[Tobbe]

The DMMF (Data Model Meta Format) we get from Prisma tells us if a field is a relational field to another model or not. We could use this information to set emptyAsUndefined on relevant form fields, instead of just relying on the "ends with Id"-naming convention.

This depends on #4353 being implemented first.

For more context:
PR: #4302
Issue: #4297

[samthuang]

hello @Tobbe - I'd like to give this issue a try if no one is actively working on this 🙂

[thedavidprice]

@samthuang if you're still interested, it would be great to have your help! Just an FYI that @Tobbe is traveling this week but I'll loop him in to check when he's back.

Feel free to start with a draft PR. Do loop in myself and Tobbe.

Lastly, I'm assuming you want to take this so I'm assigning to you now. Let me know otherwise.