Topic/explicit python env
@nnrcschmdt I've done some small improvements:
- using "virtualenv" instead of "venv" in the Readme, to be consistent with all the other Readmes
- using an explicit Python version (3.8) für vitualenv, because "python3" uses whatever is available
- Updated the "init" script in "run.sh"
If you are fine with them would be great if you could merge. Thanks :)