Setup: Staged database migration

[martastain]

This pull request changes the schema migration logic to avoid long transaction that could cause issues with larger databases.

• Old schema.public.update.sql was split to numbered files. That reduces transaction length.
• Introduced db_migration function to handle the database schema migration process, ensuring all migrations are applied in order.
• Modified the main function to use db_migration and save the current database version after applying migrations.

Since all migrations should be applied in order to handle old projects import, versioning will not be used just yet. But the DB will be prepared for it.

Since setup is crucial step, we now check whether it was executed properly and prevent the server from starting when an error occurs:

Testing

Ensure setup finishes correctly

• on a fresh instance
• after container re-creation
• after running make setup

So far, it has been tested with existing local and new cloud instances:

[BigRoy]

Not sure how to test this PR - because I'm not sure how to enforce it actually going through the migration. Did a code review, and that does look good.