add delete-userfiles flag for Domain.delete() to remove email-account data on the filesystem (if any); fixes #1239

Signed-off-by: Michael Kaufmann <d00p@froxlor.org>

customer_domains.php

@@ -26,7 +26,7 @@
 const AREA = 'customer';
 require __DIR__ . '/lib/init.php';
 
-use Froxlor\Api\Commands\SubDomains as SubDomains;
+use Froxlor\Api\Commands\SubDomains;
 use Froxlor\CurrentUser;
 use Froxlor\Database\Database;
 use Froxlor\Domain\Domain;