NewController creates a new Controller with input CustomResourceDefinition informer.

WithOpenAPIv3 returns a handler that serves OpenAPI v3 specs for CRDs, not forwarding /openapi/v3 requests to the delegate handler.

TODO(sttts): move to central place in kube.

DefaultServiceCacheSize is the default size of the OpenAPI service cache.

Controller watches CustomResourceDefinitions and publishes OpenAPI v3.

ServiceCache implements a cluster-aware OpenAPI v3 handler, sharing the OpenAPI service for equal API surface configurations.