Notebooks in VSCode VSIX to be stubbed out

[MatthewKhouzam]

Bug Description:

The Notebook API is blocking some modern python plug-ins from being compatible with Theia, as well as Jupyter notebooks. This blocks off the AI/ML crowd from using Theia. A stop-gap solution would be to stub out the APIs at first and see which ones need fixing next.

[JonasHelming]

One thing we would need to think about is how to communicate that this is stubbed. Otherwise I am in full favor of stubbing it for now. @planger

[planger]

Right, stubbing out certain API to make extensions at least work with the other API that is fully supported would certainly help in many cases. However, if something is just stubbed, I think we should make very clear that it isn't "functionally" supported.

I would maybe suggest to enhance the vscode-theia-comparator info.yml, allowing to mark namespaces/types specifically as stubbed, so that they show up as warning (orange), meaning that the types are available but actually not functional. WDYT?

[JonasHelming]

sound like a good idea to me!

[vince-fugnitto]

Closing in favor of #11786.