Investigate moving to Retrolab (JupyterLab with classic notebook interface) rather than Jupyter notebook

[lesteve]

One day the classical notebook will be gone. More details here for example. Full disclosure: I haven't read it 😉.

What need to change:

• environment to install Retrolab dependencies
• local instructions to launch Retrolab
• binder link to use RetroLab
• other things?

There may be a few issues:

• a while ago there was no way of opening .md or .py files as notebook by default you needed to right-click -> "Open as notebook" in the files view. Edit: actually this may have been fixed see Open linked .md files as notebooks in Jupyter Lab mwouts/jupytext#271 (comment). Cases which could be an issue:
  • full-index.md but the script generating it could easily be converted to create a notebook with a single markdown cell instead
  • I think it is quite rare to open .py and .md files from the files menu otherwise ...
• does it affect FUN? Ideally we don't need have to change much and FUN can stay with the classical notebook interface if they want
• other things?

[glemaitre]

From the JEP regarding the development of the v7 notebook:

https://jupyter.org/enhancement-proposals/79-notebook-v7/notebook-v7.html

I seems that it should be based on retrolab so it should be safe to experiment with retrolab.

[lesteve]

Using RetroLab would also allow us to use https://github.com/executablebooks/jupyterlab-myst, a JupyterLab extension that supports MyST inside notebooks, potentially simplifying some of our hacky scripts like https://github.com/INRIA/scikit-learn-mooc/blob/main/build_tools/convert-python-script-to-notebook.py#L96