This change adds the display(1) graphical user interface and desktop
environment with basic windowing support and the graphical terminal(1)
emulator along with integrations in chkblayout(1), chvideomode(1),
sysinstall(8), sysupgrade(8), as well as the games and ports.

Adopt the Aurora procedural wallpaper in display(1) and login(8).

Remove the obsolete dispd.

Juhani contributed keyboard and video mode APIs to the display protocol
and other miscellaneous changes.

dzwdz contributed the initial functioning window buttons, improved title
bar, window tiling, and minor bug fixes

Co-authored-by: Juhani Krekelä <juhani@krekelä.fi>
Co-authored-by: dzwdz <kg67199@gmail.com>