* chore: rework oci crate to be more composable
* feat: image pull is now internally explicit
* feat: utilize vfs for assembling oci images
* feat: rework oci to preserve permissions via a vfs
* feat: oci packer can now use mksquashfs if available
* fix: use nproc in kernel build script for default jobs, and fix DEV.md guide
* feat: working erofs backend