Refactor conversation stuff

item/ItemResource.gd

@@ -0,0 +1,13 @@
+extends Resource
+class_name ItemResource
+const Item = preload("res://item/Item.gd")
+const ItemStack = preload("res://item/ItemStack.gd")
+
+@export var item:Item.ItemId = Item.ItemId.NULL
+@export var quantity:int = 0
+
+func toItemStack() -> ItemStack:
+  var stack = ItemStack.new()
+  stack.item = item
+  stack.quantity = quantity
+  return stack