unit addWeaponItemsCargo [weapon, attachments, magazines];
unit => Object
weapon => String: weapon class name
attachments => Array: [attachment1, attachment2, attachment3]
magazines => Array: [magazine1, magazine2, ...]
magazineX => Array: [magazineName, ammoCount, muzzle]
unit addWeaponItemsCargo [weaponName, [attachment1, attachment2, attachment3], [[magazineName1, ammoCount1, muzzleName1], [magazineName2, ammoCount2, muzzleName2], ...]];
The third parameter is proposed as an array to handle weapons with UGLs/mutliple muzzles, which could have other loaded magazine.