Refactor invoice PDF generation and VAT validation

- Updated PDF template to display a fixed software code instead of "SOFTWARE".
- Changed VAT label to include tax label dynamically and set to 0% for certain conditions.
- Enhanced JavaScript for VAT number validation with asynchronous checks against the VIES database.
- Implemented debounce for VAT number input to optimize validation calls.
- Updated country settings to include country codes for VAT validation.
- Modified email sending functions in webhook handlers to use dynamic attachment names for invoices.

settings.php

@@ -4,8 +4,9 @@ defined(page_security_key) or exit;
 //=============================
 // Configuration file
 //=============================
-$domain = getDomainName($_SERVER['SERVER_NAME']);
-$file = ((file_exists(dirname(__FILE__).'/custom/'.$domain.'/settings/'.$domain.'_config.php')) ? dirname(__FILE__).'/custom/'.$domain.'/settings/'.$domain.'_config.php' : dirname(__FILE__).'/settings/config.php');
+
+$env = getenv('APP_ENV') ?: 'development';
+$file = ((file_exists(dirname(__FILE__).'/custom/'.$env.'/settings/'.$env.'_config.php')) ? dirname(__FILE__).'/custom/'.$env.'/settings/'.$env.'_config.php' : dirname(__FILE__).'/settings/'.$env.'_config.php');
 
 //Check if allowed
 if (isAllowed('settings',$_SESSION['authorization']['permissions'],$_SESSION['authorization']['permission'],'R') === 0){