Using Examples folder is not easy to follow

https://github.com/Urban-Analytics-Technology-Platform/od2net/blob/main/docs/tutorial_examples.md tutorial is bit confusing and python scripts are actually expecting a lot of harness to actually work.

1. I think it might be useful to create another image using builder stage of Dockerfile which would serve as examples "compiler"
2. README.md in examples folder would be easier to follow than a link to url to docs hidden in echo.sh
3. Simple Makefile with targets like build_docker / build_examples / test would be very helpful for newcomers to fast start
4. using symlink utils.py is not great, this folder should have a [python pkg structure](https://packaging.python.org/en/latest/tutorials/packaging-projects/) so proper importing would work.
5. autoformat and lint code with ruff.