Test: document tests and test executions to include requirements

We generate CSV files that document the test executions and the requirements affected by them.

The tests now generate an additional report:

• is supported with this tooling: https://github.com/ota4j-team/open-test-reporting
• conforms to this specification: https://github.com/ota4j-team/open-test-reporting?tab=readme-ov-file#xml-formats

A new gradle job extracts the desired data out of these XML reports and creates corresponding CSV.

A final gradle job merges all these CSV files into a large CSV that includes all the test executions.