Automatic merge from submit-queue (batch tested with PRs 49961, 50005, 50738, 51045, 49927)
adding validations on kubelet starting configurations
**What this PR does / why we need it**:
I found some validations of kubelet starting options were missing when I was creating a custom cluster from scratch. The kubelet does not check invalid configurations on `--cadvisor-port`, `--event-burst`, `--image-gc-high-threshold`, etc. I have added some validations in kubelet like validations in `cmd/kube-apiserver/app/options/validation.go`.
**Which issue this PR fixes** *(optional, in `fixes #<issue number>(, fixes #<issue_number>, ...)` format, will close that issue when PR gets merged)*: fixes #
**Special notes for your reviewer**:
**Release note**:
```release-note
Adds additional validation for kubelet in `pkg/kubelet/apis/kubeletconfig/validation`.
```
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