Implement tests for specific versions of Postgres

[iambriccardo]

We would like to run specific integration tests only for certain Postgres versions. An idea that came up in #295 (comment) is to use rstest and feature flagging to just run specific tests based on the Postgres version currently in use in CI.

[abhi-airspace-intelligence]

Working on this :) I'm looking into using testcontainers to orchestrate the lifecycle of the containers and avoid the docker compose file.

[imor]

@abhi-airspace-intelligence please remember that containers are used not only for automated testing but also for creating local environments for manual ad-hoc testing. So before we jump to testcontainers, we should evaluate whether they will allow us to keep using such environments for Iceberg/BigQuery/Postgres.

[abhi-airspace-intelligence]

Yep, I wouldn't plan on getting rid of the docker compose file (I use them extensively for local debugging).