machines/jam: Use systemd automount for /music.

Signed-off-by: aszlig <aszlig@redmoonstudios.org>
mixxx: Use smaller skin for smaller monitor.

Unfortunately the monitor in the Jam area is rather small, so until
Mixxx 0.12 is released we have to work around it that way.

Signed-off-by: aszlig <aszlig@redmoonstudios.org>
profiles/dj: Correctly autostart Mixxx using KDE.

KDE uses /share/autostart/*.desktop for automatically starting
applications. So far we started Mixxx using the sessions, which
introduced a few glitches, because the window manager was started
_after_ Mixxx.

Starting Mixxx the "KDE way" now no longer has these glitches.

Signed-off-by: aszlig <aszlig@redmoonstudios.org>
profiles/dj: Trigger shutdown on closing Mixxx.

Actually triggers the shutdown prompt with a countdown, so if the user
doesn't want the shutdown (s)he can still cancel that action.

Signed-off-by: aszlig <aszlig@redmoonstudios.org>
profiles/dj: Autostart Mixxx in fullscreen mode.

We no longer have window manager glitches now, so this won't break
things for us anymore.

Signed-off-by: aszlig <aszlig@redmoonstudios.org>
profiles/dj: Set full PCM volume of sound cards.

All sound cards managed by JACK need to have full volume, as the real
volume control is done either on the hardware mixer or within the DJ
software.

Signed-off-by: aszlig <aszlig@redmoonstudios.org>
mixxx: Add option for library location/indexing.

Sets the default library path to $HOME/Music of the DJ user, because on
the actual production system, the directory contains a symlink pointing
to the storage while containing local files as well.

Apart from the library path the options default to how it is on the
production system, so the main reason for introducing them is VM
testing.

Signed-off-by: aszlig <aszlig@redmoonstudios.org>