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 tests
**What this PR does / why we need it**:
This PR adds unit tests to sample-controller.
**Special notes for your reviewer**:
This is currently based on the munnerz:sample-controller branch. Please don't merged it until #52753 is merged.
Kubernetes-commit: dc20badcd49e5fd2ab41d4320c9c70a50d30343c
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>.
client-go: remove import of github.com/gregjones/httpcache
Moves NewCacheRoundTripper from `k8s.io/client-go/transport` to its own package. This prevents Kubernetes clients from requiring its dependencies.
This change removes the following transitive imports from `k8s.io/client-go/kubernetes`
```
github.com/google/btree
github.com/gregjones/httpcache
github.com/gregjones/httpcache/diskcache
github.com/peterbourgon/diskv
```
```release-note
NONE
```
Kubernetes-commit: 4a77bd53e88a719c612086df69a52899bbdd85af
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
