Consolidate Postgres Adapters
Migrate from asyncpg to psycopg3 for postgres queries in core:
- Testing with a minimal fastapi prototype has revealed a ~30% slowdown but a seemingly more stable pool implementation (looks like the psycopg pool features and internal queue and better multithreading support)
- still we'd get a couple hundred req/s on a single worker
- Better query interpolation
- Larger user-base
- Use same client library for migrations, web and core