GDScript: Add Global Traits

[SeremTitus]

• continues: GDScript: Add Trait System #107227

By using 'trait_name' in a .gd script file it becomes a global trait

trait_name Damageable
signal died

const MAX_HEALTH := 100
var health: int = MAX_HEALTH

func take_damage(amount: int) -> void:
	health -= amount
	print("Took damage:", amount, "Health now:", health)
	if health <= 0:
		died.emit()

func is_dead() -> bool:
	return health <= 0

func on_death()