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
```

hack/lib/util.sh

@@ -215,6 +215,7 @@ kube::util::gen-docs() {
   # to generate. The actual binary for running federation is hyperkube.
   "${genfeddocs}" "${dest}/docs/admin/" "federation-apiserver"
   "${genfeddocs}" "${dest}/docs/admin/" "federation-controller-manager"
+  "${genfeddocs}" "${dest}/docs/admin/" "kubefed"
 
   mkdir -p "${dest}/docs/man/man1/"
   "${genman}" "${dest}/docs/man/man1/" "kube-apiserver"