Accept poetry and pipenv lockfiles for installation

[abondrn]

When uv pip install is passed poetry.lock or Pipfile.lock (and any optional dependency groups, or extras) instead of requirements.txt, it could attempt to install these in the uv environment. I can only speak for myself when I say this will speed up adoption of uv in some contexts we are using it, such as executing local tests or Docker pipelines.

[bschoenmaeckers]

Should we consider re-implementing the poetry-export-plugin or calling it as a subprocess?

[zanieb]

Similar to our policy on reading pip's configuration, I don't think we can do this. I think the bullets there are a good summary of why.