Add support for UUIDv7

[mcuelenaere]

This implements https://github.com/prisma/prisma/issues/24079. The change is pretty minimal, widening the support from @default(uuid()) to @default(uuid(7)).

It leverages the existing uuid crate instead of adding a new one (uuid7).

~Right now this code is mostly untested (apart from the tests I added to psl), because I couldn't get the tests running locally. I'd appreciate some guidance in this area.~ CI runs fine