feat: Wizard shortcut on the desktop and in the launcher

- Menu item: desktop icon + launcher entry that run the newest release in Konsole.
- Icon: Valve's return icon with a gear (assets/steam-gaming-settings.svg), published with each release.
- Desktop files are written already executable, so Plasma runs them.
- VERSION 0.9.0.

setup-gamescope-boot.sh

@@ -15,11 +15,11 @@
 set -uo pipefail
 
 # Release version, see CHANGELOG.md.
-VERSION=0.8.0
+VERSION=0.9.0
 
 SCRIPT_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
 
-for lib in common state packages login-manager single-user steam-desktop steam-machine vapor-theme steamos-extras bios desktop-shortcut menu; do
+for lib in common state packages login-manager single-user steam-desktop steam-machine vapor-theme steamos-extras bios desktop-shortcut wizard-shortcut menu; do
     # shellcheck source=/dev/null
     source "$SCRIPT_DIR/lib/$lib.sh"
 done