Add field to comment and mark a requirements/svc as no longer valid

[lfvbarcus]

Summary

Requirements evolve and sometimes a requirement isn't valid anymore but we shouldn't just remove it. There should be a way to mark it as non-valid and have space to explain why.

Some reason could be.

• clash or overlap with other requirement
• changed environment, something outside of the project change.
• new insights gained

Same goes for svc.

[lfvdavid]

• inactive: (optional parameter)
  • removed / updated / etc.: (field with pre defined values for reason requirement is inactive)
    • description: (describe why requirement is inactive)
    • new_requirement: (if requirement is updated / revised in a new requirement, new ID here) (optional)

With the inactive parameter being optional we can simply ignore processing any requirement with the field present.