MCO-1972: Removes OSImageURLConfig from the build controller

[cheesesashimi]

- What I did

This decouples the Build Controller from OSImageURLConfig and makes the OSImageURL and BaseOSExtensionsImage fields on the rendered MachineConfig the source of truth for the base OS and extensions images to use for Image-Mode OpenShift. The idea is that if a different OS image is selected on a per-pool basis (e.g., one is RHEL9 and one is RHEL10 for dual-streams), then the Build Controller should use the appropriate source of truth for the appropriate pool.

- How to verify it

The best way to verify this is to create a cluster and then create a MachineConfig which overrides the OSImageURL value. The Build Controller should build a new OS image based upon the new OSImageURL value.

- Description for the changelog
MachineConfigs should be the source of truth for the Build Controller

[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

[cheesesashimi]

/test unit verify e2e-gcp-op-ocl

[cheesesashimi]

Note to reviewer: This might be a moot point since if someone is upgrading from one OCP release to another, the hashes will change. However, that means that old images may get rebuilt in the process, which is undesirable.

[openshift-ci-robot]

@cheesesashimi: This pull request references MCO-1972 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 "4.21.0" version, but no target version was set.

In response to this:

- What I did

This decouples the Build Controller from OSImageURLConfig and makes the OSImageURL and BaseOSExtensionsImage fields on the rendered MachineConfig the source of truth for the base OS and extensions images to use for Image-Mode OpenShift. The idea is that if a different OS image is selected on a per-pool basis (e.g., one is RHEL9 and one is RHEL10 for dual-streams), then the Build Controller should use the appropriate source of truth for the appropriate pool.

- How to verify it

The best way to verify this is to create a cluster and then create a MachineConfig which overrides the OSImageURL value. The Build Controller should build a new OS image based upon the new OSImageURL value.

- Description for the changelog
MachineConfigs should be the source of truth for the Build Controller

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[openshift-ci]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: cheesesashimi

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[cheesesashimi]

/test e2e-gcp-op-ocl

[openshift-ci]

@cheesesashimi: The following test 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/e2e-gcp-op-ocl	49a39f6	link	false	/test e2e-gcp-op-ocl

Full PR test history. Your PR dashboard.

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