The reason is that there were several batches of
4-port .318-01 based 801-PC systems shipped specifically
as multiseat ones (with two RX570 or three simpler GPUs),
and it's more reasonable to provide out-of-box support
for those in a new release instead of having to resort
to manual setups with alterator-multiseat, messing with
the installer-provided configuration by hand or giving up
(or, well, building a sideline installer images with
custom udev-conf packages).

The packages might need more tweaks and PCIe slot
specifics in documentation but the configurations
were taken from real systems.

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.

Now that 8CB based workstations start pouring in,
let's prepare the configuration for 1E8CB mobos
(3 PCIe slots so 1/2/3-seaters possible and tested).

alterator-users <= 10.12 and autologin-sh-functions <= 0.2.9
do not support proper multiseat autologin setup; let's at least
ask them to not confuse those installing multiseat systems with
"autologin" checkbox that will just break it (presuming single-
seat setup).

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.