Implement -D option to set configuration directory; fai.conf: don't set variables...

Get rid of /etc/grml/fai/config/grml/grml-cleanup_chroot*.  and
also drop deprecated checks. Do NOT clean up /home/grml and /root
unless using the RELEASE class.  This might make some users happy
I guess. :)

Deploy /etc/inittab, /etc/locale.gen and /etc/modules using
according fcopy commands.

Now shipping new scripts GRMLBASE/16-depmod, GRMLBASE/41-modules,
GRMLBASE/91-update-pciids, GRMLBASE/92-update-freshclam,
GRML_SMALL/90-update-alternatives, GRML_SMALL/98-clean-chroot,
RELEASE/98-clean-chroot, REMOVE_DOCS/98-clean-chroot and
LATEX/98-clean-chroot.

While at it build
/etc/grml/fai/config/files/etc/apt/sources.list/GRMLBASE based on
/etc/grml/fai/apt/sources.list to get rid of editing config files
on the fly.

This is a major Q/A rework, giving the user a much better
handling of scripts using FAI's class concept.