Automatic merge from submit-queue (batch tested with PRs 54112, 54150, 53816, 54321, 54338). 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 federation

This PR removes the federation codebase and associated tooling from the tree.

The first commit just removes the `federation` path and should be uncontroversial.  The second commit removes references and associated tooling and suggests careful review.

Requirements for merge:

- [x] Bazel jobs no longer hard-code federation as a target ([test infra #4983](https://github.com/kubernetes/test-infra/pull/4983))
- [x] `federation-e2e` jobs are not run by default for k/k

**Release note**:

```release-note
Development of Kubernetes Federation has moved to github.com/kubernetes/federation.  This move out of tree also means that Federation will begin releasing separately from Kubernetes.  The impact of this is Federation-specific behavior will no longer be included in kubectl, kubefed will no longer be released as part of Kubernetes, and the Federation servers will no longer be included in the hyperkube binary and image.
```

cc: @kubernetes/sig-multicluster-pr-reviews @kubernetes/sig-testing-pr-reviews