Do not stop after driving a spline

[pascalzauberzeug]

Our robot needs to drive continuously between two GNSS coordinates while adjusting its heading. For each segment we use drive_spline, but it stops after completing the spline drive.
This PR adds a parameter for not stopping at the end stop_at_end and does some refactoring in the Driver class

[falkoschindler]

@pascalzauberzeug Before looking into the details of this PR, can you please

• update the docstrings according to PEP 257 (indicative, no new line after the opening triple quotes),
• use reSt style (see calibration.py for some good examples), and
• fix examples/hello_bot/main.py which is still using drive_square?

Thanks!

By the way, we should probably add a note about docstrings in CONTRIBUTING.md to avoid such back and forth between styles.

[pascalzauberzeug]

@falkoschindler Sure, I will look into it. To admit, copilot wrote those docstrings 😆