Automatic merge from submit-queue (batch tested with PRs 63364, 63464). 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>.

simplify api registration

The current registration and groupmeta is only use to determine a preferred ordering to versions.  The scheme already knows about all versions, so this simply makes that knowledge official.  After doing that, the announce, registered, and apimachinery/pkg/apimachinery all drop out.

With this change we'll be able to create `install` packages for each external apigroup that accept a scheme and have suggested orderings.  This will make it possible to close the consistency gap with kubectl, client, and apiserver.

@kubernetes/sig-api-machinery-pr-reviews 
@lavalamp @smarterclayton @liggitt @sttts 

```release-note
NONE
```