docs: generate ReadTheDocs documentation using uv

This change migrates the ReadTheDocs documentation generation process to
uv from pip. These changes were done in accordance with the
recommendations from the official [ReadTheDocs documentation][1].

[1]: https://docs.readthedocs.com/platform/stable/build-customization.html#install-dependencies-with-uv



Signed-off-by: Chris Kay <chris.kay@arm.com>