added download from excel and zip in frontend

hartmann-foto-documentation-frontend/lib/controller/questionnaire_customer_controller.dart

@@ -7,6 +7,8 @@ abstract interface class QuestionnaireCustomerController {
   Future<QuestionnaireCustomerDto?> get({required int id});
 
   Future<List<int>> export({required int customerId, int? questionnaireId});
+
+  Future<List<int>> exportAll();
 }
 
 class QuestionnaireCustomerControllerImpl extends BaseController implements QuestionnaireCustomerController {
@@ -39,4 +41,10 @@ class QuestionnaireCustomerControllerImpl extends BaseController implements Ques
     }
     return runGetBytesWithAuth(uriStr);
   }
+
+  @override
+  Future<List<int>> exportAll() {
+    String uriStr = '${uriUtils.getBaseUrl()}$path/exportall';
+    return runGetBytesWithAuth(uriStr);
+  }
 }