Consider designing bootc as a library to be used by installer applications

Right now bootc only seems envisioned as a simple CLI application to install and lifecycle an ostree based system using ostree containers as the install/update payload. Given the inevitability that a use case will necessitate a higher level "installer", bootc could have an API available to use in a higher level rust application that could function itself as the installer. This would enable a distro to create a proper installer application while fully integrating the capabilities of bootc (IE: more evolved than a shell script installer).