Finish refactoring other than making sure bonuses appear on player stat side

src/items/throwable/ThrowableItem.cs

@@ -21,6 +21,8 @@ public partial class ThrowableItem : Node3D, IInventoryItem
 
   public int Count { get; }
 
+  public Guid ID => Guid.NewGuid();
+
   [Export]
   public ThrowableItemStats ThrowableItemInfo { get; set; }