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>.
staging: add boilerplate header
Follow up of https://github.com/kubernetes/kubernetes/pull/57656.
Adds boilerplate in the relevant staging repos so that they don't need to depend on code-generator's boilerplate.
**Release note**:
```release-note
NONE
```
/cc sttts fisherxu
Kubernetes-commit: 1a1643bb5df07d94330e1b16d182cee660533f91
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>.
Move unstructured conversion into pkg/runtime
Scheme conversion should support unstructured conversion natively to
allow going from unstructured to typed and back. It is not a higher
level responsibility to do that conversion because the scheme is the
only one who knows what types it supports.
@liggitt @kubernetes/sig-cli-api-reviews I am going to make Scheme support unstructured in ConvertToVersion and Convert, which means resource.Builder and the CLI can get simpler for all existing use cases where versioned and unstructured need to coexist.
Kubernetes-commit: a67abac7654cc3e05618d41191d71730cf9565ac
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>.
Introduce new `VolumeAttachment` API Object
**What this PR does / why we need it**:
Introduce a new `VolumeAttachment` API Object. This object will be used by the CSI volume plugin to enable external attachers (see design [here](https://github.com/kubernetes/community/pull/1258). In the future, existing volume plugins can be refactored to use this object as well.
**Which issue this PR fixes** *(optional, in `fixes #<issue number>(, fixes #<issue_number>, ...)` format, will close that issue when PR gets merged)*: Part of issue https://github.com/kubernetes/features/issues/178
**Special notes for your reviewer**:
None
**Release note**:
```release-note
NONE
```
Kubernetes-commit: ebe8ea73fd1a961779242dfbb629befa153e96fc
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>.
sample-controller: add example CRD controller
**What this PR does / why we need it**:
Adds a sample-controller example repository
fixes#52752
**Special notes for your reviewer**:
This is currently based on the sttts:sttts-codegen-scripts branch and should not be merged until that is (ref https://github.com/kubernetes/kubernetes/pull/52186)
**Release note**:
```
Add sample-controller repository
```
/cc @sttts @nikhita @colemickens
Kubernetes-commit: 9a7800f7d2efb88b397674672ac56f898826cf7c
