Refactor FRZR to be usable as a general purpose installer that UI tooling can hook into

[ruineka]

I'm creating this issue as a reminder for some goals we have been discussing internally. We would like to make FRZR more useful in a general purpose sense where it would take on more roles than it currently does.

• frzr-build-image would take on the responsibilities of build-image.sh found here
• To build an image you would provide frzr a manifest with packages that it will download and install
• Frzr would be able to deploy images that are not intended to be used with the BTRFS snapshot system using dd
• Frzr will be able to create a bootable usb without any external tools, including packaging in the built in image to allow for offline installations
• Frzr will be able to receive a path to an image and a path to a target drive for the user to install ChimeraOS onto any device they want from within a ChimeraOS install, or any system with frzr installed.
• Add the ability to boot from an ISO and make a snapshot of a local drive to clone it for deployment onto other devices
• Add dry run conditions to make development of new features easier