Python CLI (armarx): Setup and use own python env

Closes #85 (closed)

• Create proxy .sh scripts that source a local venv (if it exists) and call the python script
• Update CMake to symlink to the bash scripts instead of python scripts (same name as before)
• Some code modernization / style fixes

The venv should be setup by Axii: https://gitlab.com/ArmarX/meta/setup/-/merge_requests/292 If the venv does not exist, it falls back to the system environment as before. So the transition should not be a problem.