Add Requirements to coverage measuring logic

## Background
When the Requirements are supported by generated, they can be used as targets in test headers.

## Feature
- Add support to use Requirements as a target in test headers.
- Extent coverage matrixes in generated output files
- Design idea:
- keep the difference for (point for discussion)
- Feature covered by tests - direct mentions
- Feature covered by "test covered Requirements" - no direct Feature mentions in test headers