Fix the de-sync bug that made Creep War unplayable

Creating temporary units inside synchronize_choice
made the host call the random generator more times
than the rest of the clients and led to de-sync.
The temporary units weren't even used at all since
their only use, which was checking whether the
unit has at least one movement point on land, was
removed when hardcoding the creep list.
Remove creep generator timing
Take unit role in account when generating creeps
Fix choosing hero start location
Fix making creeps stronger
[cw_generate_creeps] doesn't need "key" anymore
Enable fog for Creep War
Make weapons actually cost gold again
Better variable naming