add generic Result model for leveraging Result pattern

Oqtane.Shared/Models/Result.cs

@@ -0,0 +1,21 @@
+namespace Oqtane.Models
+{
+    public class Result
+    {
+        public bool Success { get; set; }
+
+        public string Message { get; set; }
+
+        public Result(bool success)
+        {
+            Success = success;
+            Message = "";
+        }
+
+        public Result(bool success, string message)
+        {
+            Success = success;
+            Message = message;
+        }
+    }
+}