Jebel Barkal random map, fixes #5040.
Features:
* a mountain created in atlas, refs #4816
* a procedurally generated city, refs #5061
* scripted city guards and reoccuring gaia attackers
* attacker composition depend on the remaining buildings of the city
* random irrigation canals that indirectly increase the distance between the two teams
Needs map description and player feedback to become complete.
Hill based on the Napata Reconstruction hill created by Skhorn of rP21364.
Consulting By: Sundiata, Skhorn
git-svn-id: https://svn.wildfiregames.com/public/ps/trunk@21488 3db68df2-c116-0410-a063-a993310a9797