API - Search Prices - Improvements

- Use config variables for API responses.

src/DTO/ApiErrorMessage.php

@@ -11,6 +11,7 @@ class ApiErrorMessage
     const TYPE_LOGICAL_ERROR = 'logical_error';
     const TYPE_SERVER_ERROR = 'server_error';
     const TYPE_INVALID_DATE = 'invalid_date';
+    const TYPE_API_LIMIT = 'api_limit';
 
     private static $titles = array(
         self::TYPE_VALIDATION_ERROR => 'There was a validation error',
@@ -18,6 +19,7 @@ class ApiErrorMessage
         self::TYPE_LOGICAL_ERROR => 'Invalid request due to a logic error',
         self::TYPE_SERVER_ERROR => 'Error on server side',
         self::TYPE_INVALID_DATE => 'Invalid date on request',
+        self::TYPE_API_LIMIT => 'Reached API Limit'
     );
 
     private int $statusCode;