Updated API Interface

Updated API Interface to incorporate a new response model in order to simplify responses and make error handling easier.

Models/ResponseModel.cs

@@ -0,0 +1,16 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Threading.Tasks;
+
+namespace EFB.Models
+{
+    public class ResponseModel
+    {
+        //Object should be of known type from sender
+        public object Result { get; set; } = null;
+        
+        public string Error { get; set; } = null;
+        
+    }
+}