What this PR does / why we need it:
Migrate KatibCertGenerator to OPA CertController
Which issue(s) this PR fixes _(optional, in fixes #<issue number>(, fixes #<issue_number>, ...) format, will close the issue(s) when PR gets merged)_:
Fixes #2298
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- ~~[OWNERS](https://github.com/kubeflow/katib/blob/master/OWNERS)~~ [tenzen-y]
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What this PR does / why we need it: Migrate KatibCertGenerator to OPA CertController
Which issue(s) this PR fixes _(optional, in
fixes #<issue number>(, fixes #<issue_number>, ...)
format, will close the issue(s) when PR gets merged)_: Fixes #2298Checklist: