MCO-1165: rebuild annotation

[cheesesashimi]

- What I did

I added the ability for a cluster admin to request that the currently active
MachineOSBuild be rebuilt. This is done by adding the annotation
machineconfiguration.openshift.io/rebuild to the MachineOSConfig.

- How to verify it

1. Bring up an OpenShift cluster.
2. Opt into on-cluster layering by creating a MachineOSConfig.
3. Wait for the build to complete.
4. Add the annotation machineconfiguration.openshift.io/rebuild onto the MachineOSConfig.
5. The controller should delete the current MachineOSBuild and a new one should be started in its place.

- Description for the changelog
Adds rebuild functionality for OCL

[openshift-ci-robot]

@cheesesashimi: This pull request references MCO-1165 which is a valid jira issue.

Warning: The referenced jira issue has an invalid target version for the target branch this PR targets: expected the story to target the "4.18.0" version, but no target version was set.

In response to this:

- What I did

I added the ability for a cluster admin to request that the currently active
MachineOSBuild be rebuilt. This is done by adding the annotation
machineconfiguration.openshift.io/rebuild to the MachineOSConfig.

- How to verify it

1. Bring up an OpenShift cluster.
2. Opt into on-cluster layering by creating a MachineOSConfig.
3. Wait for the build to complete.
4. Add the annotation machineconfiguration.openshift.io/rebuild onto the MachineOSConfig.
5. The controller should delete the current MachineOSBuild and a new one should be started in its place.

- Description for the changelog
Adds rebuild functionality for OCL

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[openshift-ci]

Skipping CI for Draft Pull Request.
If you want CI signal for your change, please convert it to an actual PR.
You can still manually trigger a test run with /test all

[openshift-ci]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: cheesesashimi

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• OWNERS [cheesesashimi]

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[openshift-ci]

@cheesesashimi: The following tests failed, say /retest to rerun all failed tests or /retest-required to rerun all mandatory failed tests:

Test name	Commit	Details	Required	Rerun command
ci/prow/okd-scos-e2e-aws-ovn	9e106a1	link	false	/test okd-scos-e2e-aws-ovn
ci/prow/e2e-azure-ovn-upgrade-out-of-change	9e106a1	link	false	/test e2e-azure-ovn-upgrade-out-of-change
ci/prow/e2e-hypershift	9e106a1	link	true	/test e2e-hypershift

Full PR test history. Your PR dashboard.

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[sergiordlr]

Hello! it looks like that the DoARebuild in the helpers.go file is not used anymore. Should we remove it?