Make the local test runs clean up properly and work with dirty docker daemons

[achimnol]

In most local development setups, the Docker service is shared with existing workloads meaning that it may have other containers and images which aren't created by the test suite of this project. There are several test cases that fail with those containers and images, so running the test suite locally often fails while it succeeds in the CI.

Let's make them robust against existing containers and images. Also, we need to ensure repeating/interrupting tests should clean up any containers and temporary images created during the test run.