alt_disk_install command

By default, using the alt_disk_install command does the following:
1. Creates an /image.data file based on the current rootvg's configuration. A
customized image.data file can be used.
2. Creates an alternate rootvg (altinst_rootvg).
3. Creates logical volumes and file systems with the alt_inst prefix.
4. Generates a backup file list from the rootvg, and if an exclude.list file is given,
those files are excluded from the list.
5. Copies the final list to the altinst_rootvg's file systems.
6. If specified, the installp command installs updates, fixes, or new filesets into
the alternate file system.
7. The bosboot command creates a boot logical volume on the alternate boot
disk.
8. If a customization script is specified, it runs at this point.
9. The file systems are then unmounted, and the logical volumes and file
systems are renamed.
10.The logical volume definitions are exported from the system to avoid
confusion with identical ODM names, but the altinst_rootvg definition is left as
an ODM placeholder.
11.By default, the bootlist is set to the new cloned rootvg for the next reboot.