Upgrade to `next.jdbc` so we can also update to the dependencies that use it.

REMS dependencies that use next.jdbc
- conman
- luminus-migrations

Document what changes would be needed to upgrade

Start by locating the dependency declarations and usages of conman and luminus-migrations in REMS. Review the next.jdbc upgrade requirements and identify the changes those dependencies would require. Done means the required upgrade work and affected areas are documented clearly.

Written by the indexing model from the issue text.