Move unwanted AttackBase logic to the individual Armaments.
Add BuildComplete property to Building.
Clean up Attack*.
Allow Attack* to control a subset of armaments.
Change CheckFire to return the fire result.
Allow maps to define custom initial cargo and fix initial notification.
Move MuzzleFlash definition onto Armament.
Add AttackGarrisoned for allowing passengers to shoot outside. Fixes #4483.
Display fire ports in the combat debug overlay.
Add upgrade rules.
WIP: Port RA pillbox to new garrison system.
TEST: Add garrisonable jeep.
TEST: debug