debootstrap's change that enabled this feature got reverted
and now our live-config scripts are no longer used. Make sure
to put them back at the correct place when needed.
With the fix of https://bugs.kali.org/view.php?id=1871 we can
rely on the package setup to not enable the services which are
blacklisted (in preset files provided by base-files).
* Add new --variant option to build alternative images of Kali.
* Add new --version option to decide of the name of the generated file.
* Add new --subdir option to indicate where the image must be moved.