Goal

• As a user of the linux system roles for snapshots I'd like to be able to create bootable snapshot sets for platforms that support snapm.
• The boot menu interface is implemented by boom/snapm.  This feature will only be supported on the platforms that include snapm. (RHEL 9.6, Fedora 41 or higher)

Acceptance criteria

• a user of the role will be able to set a "bootable" flag when requesting snapsets
• when the bootable flag is set a new boot menu entry will be created that corresponds to the snapset