[Federation] Add reference docs for kubefed (#2937)

* Update the reference docs for kubefed

* fix syntax typos

* add period

* fix ToC links

* fix kubefed link

* revert to Kubefed title as link

* Add kubefed reference docs for the first time

* Add link for base kubefed command also

_data/reference.yml

@@ -63,7 +63,19 @@ toc:
   - docs/user-guide/jsonpath.md
   - docs/user-guide/kubectl-cheatsheet.md
 
-- docs/admin/kubeadm.md
+- title: Setup Tools
+  section:
+  - title: Kubeadm
+    path: /docs/admin/kubeadm/
+  - title: Kubefed
+    path: /docs/admin/kubefed/
+    section:
+    - docs/admin/kubefed.md
+    - docs/admin/kubefed_options.md
+    - docs/admin/kubefed_init.md
+    - docs/admin/kubefed_join.md
+    - docs/admin/kubefed_unjoin.md
+    - docs/admin/kubefed_version.md
 
 - title: Config Reference
   section: