nixos/tests/sway: init

This adds a basic test for Sway. Because Sway is an important part of
the Wayland ecosystem, is stable, and has few dependencies this test
should also be suitable for testing core packages it depends on (e.g.
wayland, wayland-protocols, wlroots, xwayland, mesa, libglvnd, libdrm,
and soon libseat).

The test is modeled after the suggested way of using Sway, i.e. logging
in via a virtual console (tty1) and copying the configuration from
/etc/sway/config (we replace Mod4 (the GNU/Tux key - you've replaced
that evil logo, right? :D) with Mod1 (Alt key) because QEMU monitor's
sendkey command doesn't support the former).

The shell aliases are used to make the sendkey log output shorter.

Co-authored-by: Patrick Hilhorst <git@hilhorst.be>

nixos/tests/all-tests.nix

@@ -385,6 +385,7 @@ in
   sssd-ldap = handleTestOn ["x86_64-linux"] ./sssd-ldap.nix {};
   strongswan-swanctl = handleTest ./strongswan-swanctl.nix {};
   sudo = handleTest ./sudo.nix {};
+  sway = handleTest ./sway.nix {};
   switchTest = handleTest ./switch-test.nix {};
   sympa = handleTest ./sympa.nix {};
   syncthing = handleTest ./syncthing.nix {};