Setup OAuth2 support (#20)

* Setup OAuth2 support

* Setup tests project

* Setup OAuth2 unit tests in CI pipeline

* Setup authorizeattribute tests

* Test

* Setup tests for AuthorizeAttribute

* Setup OAuth2 support
Unit Tests coverage

* Add OAuth2 project to release

MTSC.OAuth2/Exceptions/TokenValidationException.cs

@@ -0,0 +1,13 @@
+using System;
+
+namespace MTSC.OAuth2.Exceptions
+{
+    public sealed class TokenValidationException : Exception
+    {
+        private const string ErrorMessage = "Failed to validate access token. See inner exception for details";
+
+        public TokenValidationException(Exception innerException) : base(ErrorMessage, innerException)
+        {
+        }
+    }
+}