Those images who are fine with ALSA might still benefit
from addons like udev-alsa to have mixer levels restored
on boot; and PulseAudio-bearing images can be based upon
the same intermediate targets now without receiving the
addons they don't need.

This one should care for default mixer levels upon boot.

Split package lists:

- base alsa packages (also needed in pulseaudio-based installations)
- additional alsa packages (needed only if not using pulseaudio)
- pulseaudio packages

led@ has different kernel-modules-* package set,
some of those "standard" names are provided but
vbox* is not the case.

As our macros and helpers will grok this just fine,
let's add both variants so what's present gets in.

It's old, it uses consolekit (even if not neccessarily),
it borders obsolescence *but* removal of udev-alsa has caused
massive regressions (e.g. regular-gnome3 had soundcard mixer
levels dropped to zero from the start, regular-razorqt added
inability to poweroff to that...).

Just get it back.

This replaces the many sets of the corresponding packages
wandering all over pkglists, features and configurations;
the interface should be rather well-defined by now.