Use uv to manage ci dependencies

[tobiasdiez]

We currently just use pip install pytest and similar commands to install some python tools during our CI runs. Pip will always install the latest version of these tools, which might accidentally break our workflow. Thus, we need to lock the version used for these dependencies. The need for such a locking was raised also on the mailing list.

Here we use uv to create and easily maintain a lock file based on the dependency groups added in #37446.

For the moment, this lock file is only used to install pytest/coverage/etc during CI. Next step would be to migrate the linters to uv. uv also allows to easily install all python dependencies and python versions of the actual project, so we might want to use it to replace the python bits in sage-the-distro.

Also adds inline-metadata for tools/update-meson.py so that it can easily be run via uv without manually installing deps.

📝 Checklist

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• The description explains in detail what this PR is about.
• I have linked a relevant issue or discussion.
• I have created tests covering the changes.
• I have updated the documentation and checked the documentation preview.

⌛ Dependencies

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[tobiasdiez]

Let's wait until uv supports conda dependencies: astral-sh/uv#1703