First look at toolchain depends

[antonlacon]

This converts the compress/* packages and bcm2835-utils (and depend dtc) to depend primarily on gcc:host. Packages were chosen because they're generally straightforward packages without large depend graphs.

Edits what's using pigz:host, which at the moment is just the linux kernel on RPi devices using 64bit kernels and for all images in the script to create images.

Built test for RPi5.