For group policy control.

No use for WS, just use browser for video conferences.
This reverts commit da17ec5553867bd10c0e4d3bef4101dd0ca29005.

As suggested in ALT bug #38523.
This reverts commit 05c47eb6deedbe7de3f2882ddabf7d5887720aa6.

See ALT bug #37766.

See ALT bugs #37967, #37966.

This works around DRI3 problems resulting in caja getting
BadWindow with panel applets subsequently failing to jump
into dock (which doesn't exist just yet):

* setup-libgl-dri3-disable tunes libGL to avoid DRI3,
* setup-mate-nocomposite asks MATE to avoid compositing.
Suggested-by: Denis Medvedev <nbr@altlinux.org>

PS: added setup-mate-terminal while at that to work around
the weird theming problem resulting in dark gray on black
colour scheme in Terminal; note that there's a fork here:
pkg.in/lists/workstation/mate (wasn't avoidable easily
at the moment).

These have been:
- taken from x86_64 server iso (in substituted form);
- checked against m-p-d where needed;
- renamed from centaurus-* to centaurus/*;
- updated with s/samba-server/samba/;
- archdep bits adjusted for m-p-d/m-p syntax difference;
- amended with some tester feedback based additions included;
- pruned regarding p9/branch packages availability.

For video conferences.
Suggested by aen@.

Seems crashes are fixed:
https://bugzilla.altlinux.org/show_bug.cgi?id=37881.
This reverts commit 0c6e3a020a91e595f3077b909df2c9647b4c89a1.