Merge pull request #57224 from xiangpengzhao/kubeadm-phase-kubelet

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>.

Add phase command for dynamic kubelet configuration in kubeadm.

**What this PR does / why we need it**:
As the title says.

**Which issue(s) this PR fixes** *(optional, in `fixes #<issue number>(, fixes #<issue_number>, ...)` format, will close the issue(s) when PR gets merged)*:
partially fixes this: https://github.com/kubernetes/kubeadm/issues/571

**Special notes for your reviewer**:
/cc @luxas @fabriziopandini 
@kubernetes/sig-cluster-lifecycle-pr-reviews 

**Release note**:

```release-note
Phase `kubeadm alpha phase kubelet` is added to support dynamic kubelet configuration in kubeadm.
```

docs/man/man1/kubeadm-alpha-phase-kubelet-enable.1

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+This file is autogenerated, but we've stopped checking such files into the
+repository to reduce the need for rebases. Please run hack/generate-docs.sh to
+populate this file.

docs/man/man1/kubeadm-alpha-phase-kubelet-init.1

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+This file is autogenerated, but we've stopped checking such files into the
+repository to reduce the need for rebases. Please run hack/generate-docs.sh to
+populate this file.

docs/man/man1/kubeadm-alpha-phase-kubelet-upload.1

@@ -0,0 +1,3 @@
+This file is autogenerated, but we've stopped checking such files into the
+repository to reduce the need for rebases. Please run hack/generate-docs.sh to
+populate this file.

docs/man/man1/kubeadm-alpha-phase-kubelet.1

@@ -0,0 +1,3 @@
+This file is autogenerated, but we've stopped checking such files into the
+repository to reduce the need for rebases. Please run hack/generate-docs.sh to
+populate this file.