Alanren/new column properties (#1278)

* new column properties

* add description

src/Microsoft.SqlTools.ServiceLayer/TableDesigner/Constants.cs

@@ -27,5 +27,7 @@ namespace Microsoft.SqlTools.ServiceLayer.TableDesigner
         public const string Length = "length";
         public const string AllowNulls = "allowNulls";
         public const string IsPrimaryKey = "isPrimaryKey";
+        public const string Precision = "precision";
+        public const string Scale = "scale";
     }
 }

src/Microsoft.SqlTools.ServiceLayer/TableDesigner/Contracts/DesignerDataPropertyInfo.cs

@@ -15,6 +15,14 @@ namespace Microsoft.SqlTools.ServiceLayer.TableDesigner.Contracts
         /// </summary>
         public string PropertyName { get; set; }
 
+        /// <summary>
+        /// The description of the property
+        /// </summary>
+        public string Description { get; set; }
+
+        /// <summary>
+        /// The component type of the property
+        /// </summary>
         public string ComponentType { get; set; }
 
         /// <summary>

src/Microsoft.SqlTools.ServiceLayer/TableDesigner/Contracts/ViewModel/TableColumnViewModel.cs

@@ -16,6 +16,10 @@ namespace Microsoft.SqlTools.ServiceLayer.TableDesigner.Contracts
 
         public InputBoxProperties Length { get; set; } = new InputBoxProperties();
 
+        public InputBoxProperties Scale { get; set; } = new InputBoxProperties();
+
+        public InputBoxProperties Precision { get; set; } = new InputBoxProperties();
+
         public CheckBoxProperties AllowNulls { get; set; } = new CheckBoxProperties();
 
         public InputBoxProperties DefaultValue { get; set; } = new InputBoxProperties();