Documentation update

[enryH]

I just propose to use myst-nb to execute the notebooks directly and make some updates to the theme. Rather to show how it works.

You can read about the template here, and a see a description here

• use sphinx_book_theme (light & dark mode available)
• add notebooks to sidebar
• execute notebooks on documentation build time
• Update heading in notebooks
• Update docstrings and type annotations (there are some warnings)

[enryH]

Just a preview to showcase the current look

[enryH]

Some of the notebooks need pandas and teemi which you not install as main dependencies. And thecookbook.ipynb fails with: 'Dseqrecord' object has no attribute 'cseguid'

[enryH]

It runs the build process now in my fork, but there are plenty of warnings to deal with. At the moment I treat warnings as errors, leading the GitHub Action to fails.