[ENHANCEMENT] Add bootstrap-builder to scripts collection

Need to facilitate the building of custom bootstrap images to facilitate the possible use of the amazon-chroot Packer-builder. The amazon-ebs Packer-builder was the method used for EL 6-8 and would be preferred for EL9. It allows the used of vendor-published bootstrap AMIs, generally avoiding the need to maintain bootstrap AMIs. However, it currently appears that Kernel 5.14 (used by RHEL 9.x) through 6.1 (used by the Amazon 2023 AMIs) appear to have issues preventing the correct functioning of the pivot-root capability necessary to allow the amazon-ebs Packer-builder to work for RHEL 9+ (or Amazon 2023) image-types. Support/bug-report tickets have been opened with both Red Hat (Issue RHEL-17421) and AWS.

The amazon-chroot Packer-builder, per its detailed requirements indicates:

…This must be an EBS-backed AMI with a root volume snapshot that you have access to. Note: this is not used when from_scratch is set to true.

Maintaining a builder-owned bootstrap AMI, vice relying on the vendor-managed bootstrap AMIs, should satisfy this requirement.

No file or test is named. Start by inspecting the scripts collection and its existing amazon-ebs Packer workflow, then review the linked amazon-chroot requirements and the bootstrap AMI constraints. Done means a builder-owned bootstrap image workflow is defined and supports the requested EL9 and Amazon 2023 image types.