Add install_variant script

Author: ayufan

root/usr/libexec/board-package/install_variant.sh

@@ -0,0 +1,32 @@
+#!/bin/bash
+
+set -eo pipefail
+
+if [[ "$(id -u)" -ne "0" ]]; then
+	echo "This script requires root."
+	exit 1
+fi
+
+case "$1" in
+  minimal)
+    # no-op
+    ;;
+
+  mate|i3|lxde|xfce4|kde|gnome)
+    /usr/local/sbin/install_desktop.sh "$1"
+    systemctl set-default graphical.target
+    ;;
+
+  openmediavault)
+    /usr/local/sbin/install_openmediavault.sh
+    ;;
+
+  containers)
+    /usr/local/sbin/install_container_linux.sh
+    ;;
+
+  *)
+    echo "Unknown variant: $1"
+    exit 1
+    ;;
+esac