Merge pull request #43443 from irfanurrehman/kubefed-doc-1

Automatic merge from submit-queue (batch tested with PRs 43443, 46193, 49071, 47252)

[Federation][Kubefed] Support reference document autogeneration for kubefed

This PR is needed to address the documentation issue https://github.com/kubernetes/kubernetes.github.io/issues/2888

Apart from the code auto generation have updated some descriptions for consistency.

**Special notes for your reviewer**:
@kubernetes/sig-federation-misc 
cc @madhusudancs @csbell  

**Release note**:

```NONE
```

docs/.generated_docs

@@ -6,6 +6,12 @@ docs/admin/kube-apiserver.md
 docs/admin/kube-controller-manager.md
 docs/admin/kube-proxy.md
 docs/admin/kube-scheduler.md
+docs/admin/kubefed.md
+docs/admin/kubefed_init.md
+docs/admin/kubefed_join.md
+docs/admin/kubefed_options.md
+docs/admin/kubefed_unjoin.md
+docs/admin/kubefed_version.md
 docs/admin/kubelet.md
 docs/man/man1/cloud-controller-manager.1
 docs/man/man1/kube-apiserver.1