Add Katib release script

[andreyvelich]

I added release script to manually push images to docker.io/kubeflowkatib registry.
The image tag is :v1beta1-<commit-SHA>.
For example:

docker.io/kubeflowkatib/katib-controller:v1beta1-d5f5aa0b

Once we merge it, I will run the script to update the images.
Related: #1367.

As well, I removed legacy release-workflow since we can't use kubeflow-images-public more.

/assign @gaocegege @johnugeorge
/cc @jlewi

[kubeflow-bot]

This change is 

[k8s-ci-robot]

[APPROVALNOTIFIER] This PR is APPROVED

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[PatrickXYS]

After this PR merged, since Katib is not using Kubeflow Presubmit to release image.

We can also remove from kubernetes/test-infra

[andreyvelich]

After this PR merged, since Katib is not using Kubeflow Presubmit to release image.

We can also remove from kubernetes/test-infra

@PatrickXYS Yes, GCP prow post-submit is not needed for Katib more.

[andreyvelich]

/retest

[johnugeorge]

/lgtm