Add simulated stock history to UI

WebServer/Entities/PurchasedStock.cs

@@ -5,7 +5,9 @@ namespace Entities {
         public float Quantity { get; set; } = 0;
         public float PurchasePrice { get; set; } = 0;
         public float SellPrice { get; set; } = 0;
-        public bool Sold = false;
+        public bool Sold { get; set; } = false;
+        public DateTime BuyDate { get; set; } = new DateTime();
+        public DateTime SellDate { get; set; } = new DateTime();
     }
 
 }