Option to enable 'FULL' backup
Description
It's a pretty opinionated view that the system's SSH host keys and gitlab configuration path / secrets should be backed up separately. While I certainly agree it's possibly a good practice in some cases to do so.. It's also equally likely people have taken the time to design a secure solution for their backups in general. In that case they probably don't want the hassle of not having this information in the backup archive. (or worse not reading deeply enough to realize the backup function doesn't already do this like I had thought it did until I tested my restore like a good little Admin).
(Include problem, use cases, benefits, and/or goals) Current backups are not complete or usable without setting up Yet Another backup procedure manually.. A user might expect the backup to be complete and usable.. especially with the level of integration with omnibus. You can have a better user experience in backing up / restoring on another server.
Proposal
There should be a 'FULL' backup (and restore) mode in the rake task that preserves everything needed to do a correct restore on another box if a user chooses to enable it (print a flashy warning sure... with a link to the docs.. but if you understanding the security risks it should be an option). No different than doing a backup of an email server or whatnot..