This adds a pre-init script that is ran before systemd. This scripts prepares the system so that the rootfs will be left unaltered, but combines it with a writable ext4 filesystem, where data can be stored. Both rootfs use the same overlay, which makes it possible to preserve data while overriding one of the rootfs during an upgrade.

The bootloader specs file doesn't set earlycon anymore (this was unsupported), and rootwait is now set to have the kernel wait for the root device (required when booting without an initramfs).

Colors just spew escape codes all over the log file, so remove them.