Added status to application, response models of application for applicant and authority

SchengenVisaApi/Domains/VisaApplicationDomain/ApplicationStatus.cs

@@ -0,0 +1,12 @@
+namespace Domains.VisaApplicationDomain
+{
+    public enum ApplicationStatus
+    {
+        /// Waits for approve
+        Pending,
+        Approved,
+        Rejected,
+        /// Closed by applicant
+        Closed
+    }
+}