Validate will call the Validate function in each plugin if they implement the Validator interface.

WantsClusterQuota should be implemented by admission plugins that need to know how to map between cluster quota and namespaces and get access to the informer.

WantsDefaultRegistryFunc should be implemented by admission plugins that need to know the default registry address.

WantsQuotaRegistry should be implemented by admission plugins that need a quota registry.

WantsProjectCache should be implemented by admission plugins that need a project cache.

WantsRESTClientConfig gives access to a RESTClientConfig.