Moved interfaces, created new folders for visa requests and handlers

SchengenVisaApi/ApplicationLayer/VisaApplications/Handlers/VisaApplicationRequestsHandler.cs

@@ -0,0 +1,14 @@
+using ApplicationLayer.Applicants;
+using ApplicationLayer.VisaApplications.Requests;
+
+namespace ApplicationLayer.VisaApplications.Handlers
+{
+    /// Handles visa requests
+    public class VisaApplicationRequestsHandler(IApplicantsRepository)
+    {
+        public void HandleCreateRequest(CreateVisaApplicationRequest request)
+        {
+
+        }
+    }
+}