Adding hook to disable 70-persistent-cd.rules udev rule to prevent udev remember the cd device name both the one of the build system and the one of the live system (Closes: #706926).

Renaming remove-udev-persistent-rules.chroot hook to remove-udev-persistent-net-rules.chroot for future additional udev hooks.

Updating derivatives archive-key signature validiation to look by default at both debian and debian-maintainers keyrings.

If LB_HDD_SIZE is "auto" the size will be determined automatically as before
else it will be the given size in MB.

Also setting the default for this to "auto"

[A-Z] and [a-z] expands if there is a file or directory with one letter in the
directory.