Set up the PostgreSQL database

[anettkva]

Set up PostgreSQL with Prisma for the whole data model, seed the catalog, and run it on the VM.

Decisions are summarised in docs/DATA_MODEL.md (updated in the schema sub-issue).

Done when:

• All sub-issues are closed
• The database runs on the VM with the full catalog
• The README explains how to set it up locally and on the VM