We should not support migrations inside drivers

[Resonious]

The philosophy behind drivers is that they can be freely added and deleted without requiring any main app changes. But when a driver contains migrations, the schema becomes wrong when a driver is deleted.

For that reason, we don't actually want to support migrations inside drivers. We can remove all of the weird hacks for running scripts in the context of a driver, since those are there specifically to support migrations 😅 .