Optional more granular reporting for JUnit reports

<!-- Please only use this template for submitting enhancement requests. Implementing your enhancement will follow the KEP process: https://github.com/kudobuilder/kuttl/blob/main/keps/0001-kep-process.md --> **What would you like to be added**: https://github.com/kudobuilder/kuttl/pull/509 changed the format of the JUnit reports to be more granular. A statement at the end of the Caveats section says > If needed, I could add a knob to make this high-granularity opt-in.in the end This request is about introducing such knob to allow people to use the previous, less granular reporting format. **Why is this needed**: This potential need was already highlighted in the commit which changed the format, as highlighted above. I'd like to add that in the project I contribute, OpenStack Kubernetes Operators, we are starting to collect the results of KUTTL tests in a consistent way for internal reporting. The way each operator structured its tests is to have to have a basic mapping of 1-1 between tests and features. We don't want nor need to mark each step for reporting. So instead of having to post-process the JUnitXML file, it would be nice if kuttl could produce also (with some flag) the report in the old format.