Our docs are built with MkDocs, which requires Python and several deps.
Previously those deps were managed with Poetry, which is also written in Python.
This commit replaces Poetry with `uv`, a Rust-based Python
project/package manager, and thus removes several steps from the docs
build process.
Before:
<install Python>
<install pipx>
pipx install poetry
poetry install
poetry run -- mkdocs serve
After:
<install uv>
uv run mkdocs serve
