Since Fedora 30, license files are missing from the ISO filesystem
of live or installer images (including official builds). The source
path to these files changed when they were moved into a subpackage
named fedora-release-common (or generic-release-common).
Also, copy the license files from the installroot, rather than the
existing root filesystem.
mk-s390-cdboot has stopped working because the kernel outgrew the
hard-coded offset it used when creating cdboot.img. IBM now has a script
in s390utils that can do the same thing so use the upstream script
instead.
This drops mk-s390-cdboot script, switches the s390 templates to use
mk-s390image from s390utils.
It adds @ROOT@ to cdboot.prm, and sets inst.stage2 so that the installer
image will be found when booting the iso.
Resolves: rhbz#1891778
