8647490eae
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>. Remove unused federation docs **What this PR does / why we need it**: Federation docs are already in project [federation](https://github.com/kubernetes/federation). And /hack/generate-docs.sh here do not generate federation docs right now. So it's time to remove these docs. **Which issue(s) this PR fixes** *(optional, in `fixes #<issue number>(, fixes #<issue_number>, ...)` format, will close the issue(s) when PR gets merged)*: Fixes #56958 **Special notes for your reviewer**: **Release note**: ```release-note NONE ```