This replaces the hold_ubiquity functions. Packages that must not
be upgraded during the remaster process can be listed in the
contrib/rootfs/hold_packages file.
Since we have more than one function that reads a list of packages
from a file now, the code is moved to a new function
"get_packages_from_file".

Since all uck parts are moved to an extra file, only this file
should have the uck copying header.

scripts/remaster*: The set -e conflicted with the copying header; inserted both in the correct order.
config/: use the new default git location from master

Conflicts:
	config/Makefile.conf.defaults
	scripts/remaster_iso.sh
	scripts/remaster_rootfs.sh

This is required to escalate all failed commands to the Makefile.

Shim verifies the signature of grubx64.efi if secureboot is enabled so
it won't boot ours. Hence, we need to copy ubuntu signed .efi.

This is required to retrieve the correct iso url when downloading the
iso.

On ubuntu this is a symlink which we didn't horor before and thus broke dns in the installed image.

Note: scripts/remaster_initrd.sh does _not_ contain parts of UCK but
scripts/remaster_rootfs.sh _does_!

The content was retrieved from https://www.gnu.org/licenses/gpl.txt