[Design] Packaging and project management

[bhirsz]

Robocop and Robotidy use 'old' style packaging tools such as setuptools (with setup.py), twine and nox for poor version of the environment management. We should decide on and use more modern ways of maintaining the package.

The initial choice is uv: https://docs.astral.sh/uv/

Similarly to ruff, it's rapidly growing tool (thanks to start up invenstors) that already matches existing popular model tools such as poetry. With similiar features it additionally offers better performance and support for official PEPs (such as group dependencies).

[bhirsz]

The basic structure will be:

src/robocop
docs
tests
pyproject.toml file - all project related configuration

Main difference is that package source will be stored under src/ directory.