Update alpine to 3.19

[yubiuser]

Updates the base alpine image to 3.19.

There is no v3.19 for docker-cli yet. I kept the v3.18 base there. This PR can be extended later when such an image comes available - or it could be handled in an other PR

[yubiuser]

alpine 3.19 is now also available for docker-cli. I updated the workflow. PR is ready for review.

[yubiuser]

Latest commit removed pipenv and allowed pip to "break" the system python packages. Python is enforcing the use of venv but setting this up increases the code complexity within our docker-on-docker test suite and makes it even harder to understand. As the container are disposable and only used to run the test, I see no issue with allowing pip to --break-system-packages.