Add a CadetDockerRunner and tests

[ronald-jaepel]

This class runs CADET simulations using a command-line interface (CLI) executable that is
contained inside a Docker container. This expects the Docker container to have the
root/bin of the installation as the working folder. This gives us access to the cadet-cli and
tools such as createLWE.

ToDos:

• Add documentation
• Fix --version test (all other tests run)

[ronald-jaepel]

We could change it to expect the "root" (so one layer above bin) that is expected elsewhere but I'm tired now. Can change tomorrow.

edit: if this doesn't make sense, I can explain later.

[ronald-jaepel]

This is not a priority as CADET-Core can be installed either together with CADET-Python on the host OS or CADET-Python can be installed together with CADET-Core inside a Docker container.