Katib: Add SKIP_DB_INITIALIZATION variable of Katib DB Manager

[lkaybob]

This follow-up PR reflects a change from https://github.com/kubeflow/katib/pull/2245, which introduced a new environment variable option to skip DB initialization when Katib DB manager is run.

It updates Katib DB Manager part of Environment Variables for Katib Components.

Closes #3656

[google-oss-prow[bot]]

Hi @lkaybob. Thanks for your PR.

I'm waiting for a kubeflow member to verify that this patch is reasonable to test. If it is, they should reply with /ok-to-test on its own line. Until that is done, I will not automatically test new commits in this PR, but the usual testing commands by org members will still work. Regular contributors should join the org to skip this step.

Once the patch is verified, the new status will be reflected by the ok-to-test label.

I understand the commands that are listed here.

Instructions for interacting with me using PR comments are available [here](https://git.k8s.io/community/contributors/guide/pull-requests.md). If you have questions or suggestions related to my behavior, please file an issue against the [kubernetes/test-infra](https://github.com/kubernetes/test-infra/issues/new?title=Prow%20issue:) repository.

[google-oss-prow[bot]]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: andreyvelich, lkaybob

The full list of commands accepted by this bot can be found here.

The pull request process is described here

Needs approval from an approver in each of these files: - ~~[content/en/docs/components/katib/OWNERS](https://github.com/kubeflow/website/blob/master/content/en/docs/components/katib/OWNERS)~~ [andreyvelich] Approvers can indicate their approval by writing `/approve` in a comment Approvers can cancel approval by writing `/approve cancel` in a comment