Extend retryCmd with configurable retry and bo factor

[clarketm]

Modify retryCmd so that it accepts a number of tries and a backoffFactor.

Note: Using retries=3 and backoffFactor=1 will retain the original behavior of retryCmd (i.e. base 2 exponential). In this PR, I am also increasing the tries to 5 in an attempt to mitigate the issue described: #16130

[clarketm]

/assign @stevekuznetsov @cjwagner

[petr-muller]

/lgtm

[k8s-ci-robot]

[APPROVALNOTIFIER] This PR is NOT APPROVED

This pull-request has been approved by: clarketm, petr-muller
To complete the pull request process, please assign cjwagner
You can assign the PR to them by writing /assign @cjwagner in a comment when ready.

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

Needs approval from an approver in each of these files:

• prow/OWNERS

Approvers can indicate their approval by writing /approve in a comment
Approvers can cancel approval by writing /approve cancel in a comment

[clarketm]

/hold

I received a response from the GitHub support ticket I filed for the "not our ref" issue that drove this change. I will open an issue to summarize the problem and track the alternatives given for mitigation (including increasing retries), so the ultimate solution can be informed and objective.

#16130

[clarketm]

Can we approve/merge this as mitigation until a more permanent solution is implemented?