With StreamingCollectionEncodingToJSON and
StreamingCollectionEncodingToProtobuf, the WatchList must re-justify its
necessity. To prevent an ecosystem from building around a feature that
may not be promoted, we will stop serving list-via-watch until
performance numbers can justify its inclusion.
This also stops the kube-controller-manager from using the
list-via-watch by default. The fallback is a regular list, so during
the skew during an upgrade the "right" thing will happen and the new
StreamingCollectionEncoding will be used.