add integration tests

[SimeonEhrig]

Integration tests checks if all QED sub packages are still working with the code changes in a PR, if they use the sub package, where the PR is open.

This test PR demonstrate, how it works.

• This commit introduces an API break. Therefore the integration test job fails.
• The following up commit points to a feature branch in the commit message, which solves the API break for the using sub package. Therefore the test passes.

For more details, check the documentation.

[szabo137]

No concerns from my side, nice job, thanks!

Ready to merge!