Add the Pyodide kernel from the JupyterLite repository

[jtpio]

Import the Pyodide kernel from https://github.com/jupyterlite/jupyterlite while trying to keep most of the history.

Corresponding PR on the JupyterLite repo: jupyterlite/jupyterlite#854

Partially following https://docs.github.com/en/get-started/using-git/splitting-a-subfolder-out-into-a-new-repository:

# fresh clone of the jupyterlite repo into a temporary folder
git clone https://github.com/jupyterlite/jupyterlite tmp-pyodide-kernel
cd tmp-pyodide-kernel

# install git-filter-repo: https://github.com/newren/git-filter-repo/blob/main/INSTALL.md
# filter the two directories
python ~/git/git-filter-repo --path packages/pyolite-kernel --path packages/pyolite-kernel-extension

# go back to the jupyterlite-pyodide-kernel repo (this one)
git remote add import ../tmp-pyodide-kernel
git merge import/main --allow-unrelated-histories

# delete tmp-pyodide-kernel (not needed anymore)

This only grabs the changes that were made to the following folder and will omit changes done outside (webpack config, README, dodo, examples):

• packages/pyolite-kernel
• packages/pyolite-kernel-extension

TODO

• Bring pyolite packages with the history
• Rename to pyodide-kernel and pyodide-kernel-extension
• Keep the base and -extension packages for now. We might reconsider later whether there should be only one package to keep things simple (to be discussed)
• incorporate changes from PRs that were merged since the beginning of the split:
  • Service worker fixes, JupyterLab 3.5.1  jupyterlite#899 (needs 0.1.0b16+ to grab the IServiceWorkerManager rename)
  • Pyolite - Matplotlib: Setup inline backend by default jupyterlite#911
  • do not signal ready until initialize completes jupyterlite#900
  • Remove Image hacks, vendor and use upstream ipykernel.jsonutil jupyterlite#913
• re-add scripts and logic from dodo as plain scripts if possible (will try to not add doit to keep things simple unless very necessary). Look into using the lerna / nx declarative task pipeline: https://lerna.js.org/docs/concepts/task-pipeline-configuration
• add the CLI addon: https://github.com/jupyterlite/jupyterlite/blob/c4360950ff7341107f7f3b4ec0502b99485254d8/py/jupyterlite/src/jupyterlite/addons/pyodide.py
• Fix versioning and releaser hooks
• Fix shared webpack modules not available in the web worker
• handle Pyodide specific config. This seems to be working when testing with disablePyPIFallback (https://jupyterlite.readthedocs.io/en/latest/reference/schema-v0.html#pyolite-settings):

• Reset version to 0.0.1 to prepare for the releaser
• Fix bumping of piplite and pyodide_kernel in package.json
• Add the Python tests

[jtpio]

OK I will probably stop here for now and check the Python tests in a separate PR, since they need quite a bit of setup to work (install jupyterlite from jupyterlite/jupyterlite#854).

The kernel seems to work fine when using the jupyterlite wheel built by the released in jupyterlite/jupyterlite#854:

Follow-ups

• Publish a first jupyterlite-pyodide-kernel 0.0.x for testing
• Add it to Move the Pyodide kernel to a separate repo jupyterlite#854
• Finish Move the Pyodide kernel to a separate repo jupyterlite#854
• Check how to include jupyterlite-pyodide-kernel in jupyterlite by default for now
• More testing to make sure indexing wheels and other features specific to the pyodide kernel still work fine
• Set up RTD