Automatic merge from submit-queue (batch tested with PRs 55812, 55752, 55447, 55848, 50984). If you want to cherry-pick this change to another branch, please follow the instructions <a href="https://github.com/kubernetes/community/blob/master/contributors/devel/cherry-picks.md">here</a>.
Add Custom Pod DNS to Kubernetes API
**What this PR does / why we need it**:
Ref:
- Feature issue: https://github.com/kubernetes/features/issues/504
- Proposal: https://github.com/kubernetes/community/pull/1276
This PR adds the relevant APIs, validation check and the underlying kubelet changes.
**Which issue(s) this PR fixes** *(optional, in `fixes #<issue number>(, fixes #<issue_number>, ...)` format, will close the issue(s) when PR gets merged)*:
Fixes #NONE
**Special notes for your reviewer**:
/sig network
@kubernetes/sig-network-api-reviews
/assign @bowei @thockin
**Release note**:
```release-note
Add DNSConfig field to PodSpec and support "None" mode for DNSPolicy (Alpha).
```
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