gvfs had some multiseat support but wasn't quite there
in practice so we had to fallback from media automount
to "your flash drive is available for mounting" which
was much better than an e.g. 6-seater lottery "who wins
to get the drive automounted and presented, and who --
all the rest -- gets an error message in the face".

Just drop these.

This should have been done when reworking Workstation,
but better that late than making a copy for Education.

NB: directory name has been chosen to both sort late
    (so that functionality related checkboxes come first
    and graphics setup related ones sit down there), and
    to relate to X11 as well.

This started as a three-seater 801-PC support for
ALT Education 9.0 for Elbrus.