[release-4.21] OCPBUGS-88473: Add a flag to disable installing bootloaders

[sunku5494]

Disables bootloader installations (calls to grub-install) for security reasons as part of the mitigation for CVE-2026-43003.

Depends-On: https://review.opendev.org/c/openstack/ironic/+/990724
Related-Bug: 2148310
Change-Id: I10c88426d5838820ecf6853dca5b3878dc29bdf4

(cherry picked from commit 6cd463a) (cherry picked from commit c0eb928)

[openshift-ci-robot]

@sunku5494: This pull request references Jira Issue OCPBUGS-88473, which is invalid:

• release note text must be set and not match the template OR release note type must be set to "Release Note Not Required". For more information you can reference the OpenShift Bug Process.
• expected Jira Issue OCPBUGS-88473 to depend on a bug targeting a version in 4.22.0 and in one of the following states: VERIFIED, RELEASE PENDING, CLOSED (ERRATA), CLOSED (CURRENT RELEASE), CLOSED (DONE), CLOSED (DONE-ERRATA), but no dependents were found

Comment /jira refresh to re-evaluate validity if changes to the Jira bug are made, or edit the title of this pull request to link to a different bug.

The bug has been updated to refer to the pull request using the external bug tracker.

Details

In response to this:

Disables bootloader installations (calls to grub-install) for security reasons as part of the mitigation for CVE-2026-43003.

Depends-On: https://review.opendev.org/c/openstack/ironic/+/990724
Related-Bug: 2148310
Change-Id: I10c88426d5838820ecf6853dca5b3878dc29bdf4

(cherry picked from commit 6cd463a) (cherry picked from commit c0eb928)

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