Feature: Postgres support

[albinmedoc]

Is your feature request related to a problem? Please describe.
Im running Wishlist in Kubernetes and have the volumes mapped to NFS share. Sqlite doesn't play well with NFS as the database gets locked.

Describe the solution you'd like
Make it possible to use postgres as database. The ORM should already support it.

Describe alternatives you've considered
Don't map the volume to an NFS, and have the storage stored separated from all my other applications.

[cmintey]

It's unfortunate that SQLite doesn't play well with network shares. Prisma used to directly support having multiple database engines, but removed it a while ago (prisma/prisma#3834). I believe there are still some (somewhat hacky) ways to achieve it, which I can look into.