tox was used as sort of a make target to run unit tests
and more in a python virtualenv. However, since we switched
everything to poetry it's no longer needed to let tox create
the python virtual environments. This commit moves the tox
targets into the Makefile and adapts the github workflow
files accordingly. In addition the scripts container based
tests were re-activated and fixed such that they succeed
again.
Add integration tests for functions.sh
Implement a container based test system to run shell code for testing.
The concept utilizes pytest-testinfra and runs a container per test.
The nested container in a container feature is supported by the github
actions workflow. Thus the integration of this testing concept runs in
the github actions CI rather than on gitlab
