feat: get best trader offer for items

TODO: Make a better conversion for USD/EUR to RUB

Plugin/Extensions/ItemExtensions.cs

@@ -16,8 +16,23 @@ namespace LootValueEX.Extensions
         /// <param name="item">The item to check.</param>
         /// <returns>True if the item has been examined, false otherwise.</returns>
         internal static bool IsExamined(this Item? item) => item != null && ClientAppUtils.GetMainApp().GetClientBackEndSession().Profile.Examined(item);
+        internal static bool IsStacked(this Item? item) => item != null && (item.StackObjectsCount > 1 || item.UnlimitedCount);
         internal static string PrehashTemplate(this Item? item) => string.Format("{0}|{1}|{2}", item?.TemplateId, item.GetDurability(), item.GetUses());
 
+        internal static Item? UnstackItem(this Item? item)
+        {
+            if (item == null)
+                return null;
+
+            if (!item.IsStacked())
+                return item;
+
+            Item? itemClone = item.CloneItem();
+            itemClone.StackObjectsCount = 1;
+            itemClone.UnlimitedCount = false;
+            return itemClone;
+        } 
+
         /// <summary>
         /// Retrieves the value of a specific attribute from an item.
         /// </summary>