Add polybar launch script

applications/polybar/launch-script.sh

@@ -0,0 +1,14 @@
+#!/usr/bin/env sh
+
+# Terminate already running bar instances
+killall -q polybar
+
+# Wait until the processes have been shut down
+while pgrep -x polybar >/dev/null; do sleep 1; done
+
+# Launch polybar
+if [ $GDK_SCALE = 1 ]; then
+   polybar i3-ldpi &
+else
+  polybar i3 &
+fi