Have 'Go Back' option during install steps

[innovate-support]

During installation steps it would be really helpful to have a 'Go Back' option to back up to previous screens in case of mistyping or something. Currently there's only a 'Cancel' option, which ends the process and requires the install to be completely restarted. This is cumbersome if trying to work through errors.

[weslambert]

Unfortunately, TMK, this is a limitation of Whiptail, and we aren't able to easily accommodate this at this time. We certainly understand how this can be frustrating, and this may be addressed if/when we move to another menu system.