Buff elephant archer after rP18286 made it slow, rP18363 removed the capturing ability, rP18453 removed the resource gathering ability and rP19333 made it fat.
Double the damage output, HP and cost.
Add armor and metal cost for consistency with the War Elephant.
Differential Revision: https://code.wildfiregames.com/D436
Reviewed By: fatherbushido
Tested By: borg-
Values agreed with: Grugnas, nigel87