As per https://docs.docker.com/engine/network/links/, links are not recommended to use anymore. Also, it is currently not possible to use (Docker)ComposeContainer#withExposedService on podman as it uses links via an API addLink and it looks as if podman doesn't offer links at all (while docker does). The addLink API has been deprecated almost 10 years ago and this PR addresses this deprecation and replaces it with a network based approach.

Sadly, I cannot run all tests in one go on my machine. Tests that fail in the "big run" work nicely when I run them individually. So it would be really great if somebody could do a review (I must have missed something in there!) and I would be happy to see the tests on the CI here, so i can see the results and continue on this PR.