removing unmigrated CI jobs ahead of prow control-plane migration

[BenTheElder]

See: https://groups.google.com/a/kubernetes.io/g/dev/c/qzNYpcN5la4

We're going to track the removals here, so they can be identified if anyone wishes to re-introduce removed jobs by recreating them on community owned resources.

NOTE: Please do not jump on removing all of them outright, we're going to do this carefully in phases (e.g. #33129), between now and the prow control plane Migration over the next few weeks.

We are tracking some additional complications in #32432

[BenTheElder]

First up: ~unused manual scalability presubmits #33229

[BenTheElder]

Secrets store CSI: #33231, #33232

Then we can drop the legacy GCP janitors ref #33129, as no more jobs using external GCP/GCE resource should exist. [double checking ...]

Later when more of the jobs are dropped, we will also manually turn down the boskos deployment in cluster: default.

[BenTheElder]

GCP project janitor jobs: #33234, following the above removals.

[BenTheElder]

VSphere Jobs: #33241, #33245, #33246 and fix in #33249

Janitor excluded, we'll do that as a follow-up in a bit when there haven't been any other vsphere job runs for a while. I'm going to trigger an early run of that janitor now. xref #33129

[BenTheElder]

This will be completed with the removal of assorted non-migrated azure jobs in #33272

There are some follow-up actions to begin eliminating the default-cluster from prow and cleanup ahead of the control plane migration. I'll start on those after it merges.

[BenTheElder]

Scaled the legacy cluster down to 0, we have some more cleanup to do next. (like #33274)