Use uv for dependency management and versioning

[pederhan]

This PR adds dependency management backed by a uv lockfile. Building, installing and running the project has been fully migrated to uv in CI as well.

Development dependencies

Development dependencies are now specified as PEP 735 dependency groups. Dependency groups are not yet supported by pip, so for now, this means the development environment can only be installed with uv. Mreg itself does not require uv.

Docker image

Since uv does not support the pip wheel interface, we still have to install pip in the build stage of the dockerfile to build wheels for all of the project's dependencies. This complicates the build stage somewhat.

Versioning

The project is now versioned with setuptools-scm, which uses git tags to determine the project version. This necessitates git being installed wherever the project is built (such as in the build stage of the dockerfile).

The project's version can be accessed via mreg_cli.__about__.__version__ (or the short-hand import mreg_cli.__version__).

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Why not use uv python install in the Dockerfile?

https://docs.astral.sh/uv/guides/integration/docker/#installing-python-in-musl-based-images

[terjekv]

LGTM.

[pederhan]

django-rest-framework is still locked to 3.14.0, which has its own set of issues, but we will not resolve that in this PR. The container image unit tests will remain broken until we can fix that in a different PR.

[coveralls]

coverage: 98.659%. remained the same
when pulling 8fd1108 on pederhan:uv-pyproject-versioning
into 8c8b07c on unioslo:master.