[mwien]

Context

Closes SAP/ai-sdk-python-backlog#77.

What this PR does and why it is needed

Introduces the Ruff formatter to the code base and formats all files to satisfy the format check. Concretely:

• Ruff format check is added to CI, however the formatter is not run automatically, this needs to be handled by the dev
• All files are formatted with Ruff
• The option skip_magic_trailing_comma is set to true. When we introduce the linter, we need to set isort.split-on-trailing-comma=false to ensure everything is working correctly (there is currently a warning for this). Other options are so far left at their defaults. See a list of possible options here.

Definition of Done

• Code is tested (Unit, Integration, E2E)
• Error handling created / updated & covered by the tests above
• Documentation updated
  • Only Public APIs are allowed to be used in documentation/tutorials/sample code
• (Optional) Aligned changes with the JS/TS and Java SDK
• (Optional) Release notes updated -->