[UPDATE][I3] Move Xautolock toggle to script

To allow notifications when toggling the state of Xautolock, the logic
has been moved to its own script.

scripts/toggle-xautolock

@@ -0,0 +1,16 @@
+#!/bin/sh
+
+case "$1" in
+    enable|disable)
+        ;;
+    *)
+        echo "Unkown command '$1'" >&2
+        echo "Usage: '$0 <enable|disable>'" >&2
+        exit 1
+        ;;
+esac
+
+xautolock "-$1"
+
+notify-send -u low "Toggled Xautolock (${1}d)" \
+    -h string:x-canonical-private-synchronous:xautolock-toggle # Override previous one