pgx v4 (github.com/jackc/pgx/v4) will go EoL in July 2025. We should upgrade to pgx v5 before then to ensure we're on a supported version. This needs to be for both clair and claircore.

Checklist:

• Update handling of UUID to rely on the Scan method offered by the library.
• Update handling of JSONB fields to remove intermediary object translation.
• Add version (and version range) scan plans + encode plans (already defined here https://github.com/hdonnay/claircore/tree/hack/db-updates).