Add a system tests workflow

[MakisH]

Similarly to precice/dumux-adapter#80

Depends on precice/tutorials#758, which also adds the micro_manager_test test suite.

TODO:

• Create the label (I can do that)
• Enable the runner for this repo (see runner groups)
• Run the tests: see this run
  • Currently failing, until Modify Python requirements.txt in tests tutorials#857 gets merged.

Checklist:

• I made sure that the CI passed before I ask for a review.
• I added a summary of the changes (compared to the last release) in the CHANGELOG.md. -> Do we need that?
• If necessary, I made changes to the documentation and/or added new content. -> Not needed
• I will remember to squash-and-merge, providing a useful summary of the changes of this PR.

[IshaanDesai]

Thanks a lot! The Micro Manager badly needs regression tests, so this is a step in the right direction.

A changelog entry is not necessary as this is not a user-side change.