[MNT] move CI to uv (assume you have a global uv/uvx installed)

[tschm]

Add this stage we do not yet install uv/uvx. We assume the user is familiar with uv.

[tschm]

@fkiraly This is the move to uv. I have updated the pyproject.toml file for it, removed poetry.lock and created a uv.lock file with uv sync --all-extras Again, I have deactivated the linters (causing mild problems)

[tschm]

@fkiraly this could be merged

[tschm]

Fair point to use uv pip install.