Automatic merge from submit-queue (batch tested with PRs 45835, 45389)
Introduce visibility rules to kubernetes code.
**What this PR does / why we need it**:
Use rules to identify "bad" dependencies on kubectl code for later refactoring or removal, and prevent their reintroduction.
**Which issue this PR fixes**
First in a series of PRs to address kubernetes/community#598
**Release note**:
```release-note
NONE
```
**What this PR does / why we need it**:
Visibility rules allow dependency control. The rules currently in
place make all targets public, to override the default state of
private. This PR removes public visibility from kubectl code. It
uses specially named pacakge groups to identify "bad" dependencies on
kubectl code for later refactoring or removal.
**Which issue this PR fixes**
First in a series of PRs to address kubernetes/community#598
**Release note**:
```release-note
NONE
```
