As a user, I can configure requirement relationship using sub-tasks and issue links at the same time

As a user, I can configure requirement relationship using sub-tasks and issue links at the same time.

On Xray Cloud, it's possible to define the hierarchichal requirement relationship  using a combination of Epic=>Story, sub-tasks, custom issue links. On Xray DC we can only use Epic=>Story + custom issue links or Epic=>Story + subtasks.

The idea would be to align both implementations.

Note: Whole issue links are commonly used to define high-level requirement, sub-tasks are many times use to implement several aspects of the user story or to even define acceptance criteria that can be covered by tests.