Added authentication and authorization, updated dependency injections, removed hard-coded connection string

SchengenVisaApi/ApplicationLayer/GeneralNeededServices/IDateTimeProvider.cs

@@ -0,0 +1,8 @@
+namespace ApplicationLayer.GeneralNeededServices
+{
+    public interface IDateTimeProvider
+    {
+        /// Returns current date and time
+        DateTime Now();
+    }
+}