Merge pull request #49112 from gmarek/eventAPI

Automatic merge from submit-queue (batch tested with PRs 55952, 49112, 55450, 56178, 56151). 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>.

New API group for Events.

Fix kubernetes/enhancements#383

cc @shyamjvs

```release-note
Add events.k8s.io api group with v1beta1 API containing redesigned Event type.
```

Kubernetes-commit: 60c20901911c710491a57eb8b9c48850cdbab054

Author: k8s-publish-robot