Add API to re-schedule controller execution also for DeleteControl

[csviri]

See the same for update control: #570
Delete control is now an enum so will need an API change.

[cortex93]

Is it for when deleteResource returns DeleteControl.NO_FINALIZER_REMOVAL, so the controler can decide to reconcile later (e.g. when a non transient error occured) ?

[csviri]

@cortex93 usually its a special case. We had use cases when non-k8s resources were managed, and was waiting for events from those systems, while not all the external systems were cleaned up properly we returned NO_FINALIZER_REMOVAL so we don't block the Thread. In other words it's kinda for async cleanup usually for external systems.