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.

I've shipped modesetting-based images and mga2-based ones
(and reverted to modesetting by hand "when it MUST work");
let's just do it right.

NB: found out that Name fields must NOT contain ";"
    or alterator-apt chokes in runtime (not fatal
    but still spectacular, see #35526).