Automatic merge from submit-queue (batch tested with PRs 65566, 67959, 68029, 68017, 67263). If you want to cherry-pick this change to another branch, please follow the instructions here: https://github.com/kubernetes/community/blob/master/contributors/devel/cherry-picks.md.

Move kubelet ComponentConfig external types to `k8s.io/kubelet`

**What this PR does / why we need it**:
This PR implements most of kubernetes/community#2354 for the kubelet.
The PR:
 - Moves `k8s.io/kubernetes/pkg/apis/kubeletconfig` as-is to `k8s.io/kubernetes/pkg/apis/config` as agreed
 - Moves the external types to the new staging repo `k8s.io/kubelet`, in the `k8s.io/kubelet/config/v1beta1` package.
 - Makes `k8s.io/kubernetes/pkg/apis/config/v1beta1` source the types from `k8s.io/kubelet/config/v1beta1`. The defaulting and conversion code is kept in this package as before.
 - All references to these packages have been updated.

**Which issue(s) this PR fixes** *(optional, in `fixes #<issue number>(, fixes #<issue_number>, ...)` format, will close the issue(s) when PR gets merged)*:
ref: kubernetes/community#2354

**Special notes for your reviewer**:

This PR depends on getting https://github.com/kubernetes/kubernetes/pull/67780 merged first.

**Release note**:

```release-note
kubelet v1beta1 external ComponentConfig types are now available in the `k8s.io/kubelet` repo
```
/assign @sttts @mtaufen @liggitt