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

SchengenVisaApi/ApplicationLayer/AuthServices/NeededServices/ITokenGenerator.cs

@@ -0,0 +1,9 @@
+using Domains.Users;
+
+namespace ApplicationLayer.AuthServices.NeededServices
+{
+    public interface ITokenGenerator
+    {
+        string CreateToken(User user);
+    }
+}