Automatic merge from submit-queue (batch tested with PRs 54773, 52523, 47497, 55356, 49429). 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>.

Deduplicate RC/RS controller code.

The code was already 99% similar between RC and RS. This is a wild idea to try to deduplicate the two controllers in a type-safe manner without adding tons of boilerplate, and without using code generation.

They are still separate resources and separate worker pools. This is a refactor that isn't intended to change any behavior.

```release-note
ReplicationController now shares its underlying controller implementation with ReplicaSet to reduce the maintenance burden going forward. However, they are still separate resources and there should be no externally visible effects from this change.
```

ref #49429