Cookiecutter update

[Zeitsperre]

Pull Request Checklist:

• This PR addresses an already opened issue (for bug fixes / features)
  • This PR fixes #xyz
• (If applicable) Documentation has been added / updated (for bug fixes / features).
• (If applicable) Tests have been added.
• This PR does not seem to break the templates.
• CHANGELOG.rst has been updated (with summary of main changes).
  • Link to issue (:issue:number) and pull request (:pull:number) has been added.

What kind of change does this PR introduce?

• Updates the cookiecutter template to the latest commit
• CI now uses a CI folder to manage pip dependencies
• checks for YAML format and code quality are stricter (via ruff)
• Python3.13 has been added to the list of supported Python versions
• Development dependency and documentation updates
• flake8-alphabetize has been replaced by ruff
• numpydoc-validate has been staged for integration in linting
• There is now a license statement in the top-level __init__.py

Does this PR introduce a breaking change?

Not really. The linting checks are more intense.

Other information:

numpydoc-validate is not enabled since the changes are significant and require input from multiple developers. These should come about in another PR.