Improve developer tooling

[dalito]

This PR adds some tools to help with writing consistent, well-formatted schemas with fewer spelling errors.

• add typos spell checker as gh-action in this repository (but not in the created project)
• add pre-commit config for the following tools:
  • some checks from pre-commit, e.g. on trailing white-space
  • codespell - was already used in a gh-action of the repo but had to be added to pre-commit
  • yamllint - linter for yaml files
  • ruff - Python code formatter and linter
  • typos - spell checker (detects other errors than codespell)

The presence of .pre-commit-config.yaml does not activate the tools so everyone can decide if they want to use them. To enabled the checks, install pre-commit with pipx install pre-commit and then activate it in the project by running pre-commit install at the root of the project. Once installed pre-commit will run the checks on every commit and reject the commit if errors are found; it will try to auto-correct several types of errors. It is also possible to run the checks manually with pre-commit run -a.

The checks in pre-commit are not run as gh-actions in the created project. This may be added later (as an option).