Merge pull request #55204 from vladimirvivien/k8s-csi-volume-source

Automatic merge from submit-queue. 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>.

Kubernetes CSI - Persistent Volume Source Type

**What this PR does / why we need it**:
This PR is to track the addition of new API type `CSIPersistentVolumeSource` that will be used as PersistentVolume for storage sources managed by CSI drivers.

**Which issue(s) this PR fixes** *(optional, in `fixes #<issue number>(, fixes #<issue_number>, ...)` format, will close the issue(s) when PR gets merged)*:
xref kubernetes/enhancements#178

**Special notes for your reviewer**:
- Implements API `PersistentVolume` type `CSIPersistentVolumeSource`
- Part of implementation for kubernetes/enhancements#178
- Designed at kubernetes/community#1258

Other CSI Volume Plugin PRs:
- Plugin Mounter/Unmounter kubernetes/kubernetes#54529
- Plugin Attacher/Detacher kubernetes/kubernetes#55809

**Release note**:

```release-note
NONE
```

Kubernetes-commit: 928c85fc997a49e607a94960f1680d9a87b8934f