Add support for using generic SQL queries to filter EditData rows. (#605)

src/Microsoft.SqlTools.ServiceLayer/EditData/Contracts/EditInitializeRequest.cs

@@ -31,6 +31,11 @@ namespace Microsoft.SqlTools.ServiceLayer.EditData.Contracts
         /// The type of the object to use for generating an edit script
         /// </summary>
         public string ObjectType { get; set; }
+
+        /// <summary>
+        /// The query used to retrieve result set
+        /// </summary>
+        public string QueryString { get; set; }
     }
 
     /// <summary>