Switch to uv for dependency management

[mpharrigan]

• use uv to lock dependencies, but still export them to requirements.txt files so the CI is not changed.
• Bump supported Python to 3.11 (NEP 29)

xref #1807

[fdmalone]

Are you sure you want to include the uv.lock file?

[mpharrigan]

Yes, it says to:

https://docs.astral.sh/uv/guides/projects/#uvlock

Note that we already do the (worse) equivalent of this with the dev.env.txt and other *.env.txt files. With this PR, users will still get the loose, pip-resolved requirements if they just pip install qualtran, and developers can continue to use pip install -r dev_tools/requirements/dev.env.txt if they want a fixed, complete developer environment; or they can use uv themselves.

(edited with correct link)

[fdmalone]

oh cool, just noticed in other projects it isn't included (not sure why). LGTM