Added an objective to retake the PALA highway base if it is lost. If completed, a convoy will spawn, as well as aa and supply units which should drive to the highway, retake it, and park in defensive formations.

Hopefully fixed pathing for units getting stuck during the PALA landing.

Added roads to and from city with depots.

Fixed some objective visibility, reworked and buffed final bunker, as players were killing it too quickly :)

Changed up desert base slightly.