Update to JupyterBook 1.0

[scottyhq]

May need to update link syntax in some notebooks https://github.com/executablebooks/jupyter-book/releases/tag/v1.0.0

[scottyhq]

Since we use conda-lock we require releases from pypi or conda-forge so are blocked by having a sphinx-exercise extension release executablebooks/sphinx-exercise#69

The easiest solution might be to remove the extension and just use markdown dropdowns to reveal exercise solutions - see #88. You loose automatic numbering

FWIW In the long run, development of jupyterbook 2.0 also seems to be moving away from depending on sphinx (and therefore sphinx extensions) https://executablebooks.org/en/latest/blog/2024-05-20-jupyter-book-myst/