docs: remove katib workflow

[gonmmarques]

What this PR does / why we need it:
Fixes # #2442
Relates also to kubeflow/website#3906

Let me know if I missed something.

Checklist:

• Docs included if any changes are user facing

In the spirit of Hacktoberfest, and if this PR is accepted, please consider adding the label "hacktoberfest-accepted”. Thanks.

[Electronic-Waste]

/rerun-all

[Electronic-Waste]

/label ok-to-test

[google-oss-prow]

@Electronic-Waste: The label(s) /label ok-to-test cannot be applied. These labels are supported: tide/merge-method-merge, tide/merge-method-rebase, tide/merge-method-squash, lifecycle/needs-triage. Is this label configured under labels -> additional_labels or labels -> restricted_labels in plugin.yaml?

In response to this:

/label ok-to-test

Instructions for interacting with me using PR comments are available here. If you have questions or suggestions related to my behavior, please file an issue against the kubernetes/test-infra repository.

[andreyvelich]

/ok-to-test

[andreyvelich]

/rerun-all

[Electronic-Waste]

Can be merged after kubeflow/website#3906

[andreyvelich]

Thanks for updating this @gonmmarques!
/lgtm
/approve

[google-oss-prow]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: andreyvelich, Electronic-Waste

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