Automatic merge from submit-queue (batch tested with PRs 42177, 42176, 44721)
CronJob: Respect ControllerRef
**What this PR does / why we need it**:
This is part of the completion of the [ControllerRef](https://github.com/kubernetes/community/blob/master/contributors/design-proposals/controller-ref.md) proposal. It brings CronJob into compliance with ControllerRef. See the individual commit messages for details.
**Which issue this PR fixes**:
This ensures that other controllers do not fight over control of objects that a CronJob owns.
**Special notes for your reviewer**:
**Release note**:
```release-note
CronJob controller now respects ControllerRef to avoid fighting with other controllers.
```
cc @erictune @kubernetes/sig-apps-pr-reviews
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