Add VB.NET implementation

vbnet/GildedRoseKata/Item.vb

@@ -0,0 +1,9 @@
+Public Class Item
+    Public Property Name As String
+    Public Property SellIn As Integer
+    Public Property Quality As Integer
+
+    Public Overrides Function ToString() As String
+        Return Me.Name & ", " & Me.SellIn & ", " & Me.Quality
+    End Function
+End Class