[A27] [Skirmish Maps] Some minor improvements to some maps and "new" keyword added to a few

Arabian Oases: Added "new" keyword
Sporades Islands: Added "new" keyword, gave both players a free starting Scout Ship. Added a capturable CC on the unoccupied north island. Added 2 Gaia Treasure Ships.
Syria: Added some Ruins and Shrines.
Watering Holes: Minor tweaks to grass placement.
Zagros Mountains: Added some Shrines and swapped out the Gaia fields and farmsteads for capturable Mill_Fields and Mills.