Generate API documentation

[imagejan]

For using the functionality of this repository in other projects, it is essential to have some API documentation accessible. Most of the methods have docstrings, so usage within an IDE is fine.
For better accessibility, I suggest also rendering a documentation website, using readthedocs and GitHub actions, for example.

[hkabbech]

An API documentation containing the main purposes, instructions, module docstrings and the contribution guideline is now available at the following address: https://tracksegnet.readthedocs.io/en/latest/
For each pull request, an updated documentation is generated through a GitHub action