- Added detailed ÖTO-compliant masterdata documentation (`OETO_STAMMDATEN.md`) to the `masterdata` service.
- Updated the `README.md` to reference the new documentation and provide further context.
- Consolidated age group criteria, competition classes, splitting rules, and judging methods for uniform reference.
Signed-off-by: Stefan Mogeritsch <stefan.mo.co@gmail.com>
