The code imports 'bluetooth._bluetooth' which requires the PyBluez package
(not bluepy). PyBluez provides Classic Bluetooth support needed by utils.py
and sensor_reader.py.
- Add pybluez>=0.31 to both requirements.txt and pyproject.toml
- Keep bluepy and paho-mqtt as they are also needed
- bluez system package also needed (already in debian/control)
Fixes: ModuleNotFoundError: No module named 'bluetooth'
