feat(manager/uv): support uv.toml configuration

[mkniewallner]

Note

Keeping the PR as a draft for now, because it requires some changes in the end (astral-sh/uv#7007), and it's based on the changes made in #31186.

Changes

Additionally to reading uv configuration from [tool.uv] in pyproject.toml, support reading configuration from uv.toml, which supports a subset of the options available in pyproject.toml.

Context

Closes #31188.

Documentation (please check one with an [x])

• I have updated the documentation, or
• No documentation update is required

How I've tested my work (please select one)

I have verified these changes via:

• Code inspection only, or
• Newly added/modified unit tests, or
• No unit tests but ran on a real repository, or
• Both unit tests + ran on a real repository

[mkniewallner]

For now there is no need for this in the end, as none of the uv settings currently supported by Renovate can be set to uv.toml, additionally to pyproject.toml (https://docs.astral.sh/uv/reference/settings/). There might come a time where we implement a setting that could be set in both files, but until then, closing this PR.