Deprecate kubeflow/katib ECR repos

[PatrickXYS]

/kind bug

What steps did you take and what happened:
As a post item of deprecating optional-test-infra, we'll deprecate kubeflow/katib ECR repos provided by optional-test-infra.
Serves as sub-issue of kubeflow/testing#1008

What did you expect to happen:
Deprecate kubeflow/katib ECR repos provided by optional-test-infra

Repo List:
kubeflow/katib: 809251082950.dkr.ecr.us-west-2.amazonaws.com/katib/v1beta1/

• cert-generator
• earlystopping-medianstop
• file-metrics-collector
• katib-db-manager
• suggestion-chocolate
• suggestion-darts
• suggestion-enas
• suggestion-goptuna
• suggestion-hyperband
• suggestion-hyperopt
• suggestion-optuna
• suggestion-skopt
• tfevent-metrics-collector
• trial-darts-cnn-cifar10
• trial-enas-cnn-cifar10-cpu
• trial-enas-cnn-cifar10-gpu
• trial-mxnet-mnist
• trial-pytorch-mnist
• trial-tf-mnist-with-summaries

@kubeflow/wg-automl-leads I believe those repos are not used in deployment by kubeflow/katib, please confirm those repos are not in-use, if not, let's find alternatives by July.

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[PatrickXYS]

@andreyvelich Hey Andrey, I believe Katib is not using the above repos since I didn't see any version tags attached to the image, e.g, v1.1, v1.2, etc.

Could you help confirm on Katib side? Thanks!