This ticket proposes to make JupyterLab a standard package.

This would require converting jupyterlab and jupyterlab_widgets from "pip" packages to "normal" packages (https://doc.sagemath.org/html/en/developer/packaging.html#package-source-types)
and adding their dependencies as "normal" packages as well.
#34450 allows us to use (non-platform) wheels instead of source packages, which simplifies things because we can avoid Javascript dependencies that are only needed at build time.

This is a mechanical task, which is assisted by https://doc.sagemath.org/html/en/developer/packaging.html#utility-script-to-create-packages but not fully automated (dependencies needs to be updated manually).

Discussion/vote:
https://groups.google.com/g/sage-devel/c/orUpb-YXIHk/m/GIxiKN4eDQAJ

Depends on #32069
Depends on #34450
Depends on #34454

CC: @slel @egourgoulhon @antonio-rojas

Component: notebook

Keywords: JupyterLab

Issue created by migration from https://trac.sagemath.org/ticket/24904