Forward mailcow-ui-domain to the docs

We need a additional variable for the mailcow-ui-domain, if the domain used for the mailcow ui differs from the hostname. Otherwise our users will get the login promt, when they try to access the mobileconfig file.

data/web/user.php

@@ -76,7 +76,7 @@ elseif (isset($_SESSION['mailcow_cc_role']) && $_SESSION['mailcow_cc_role'] == '
   $username = $_SESSION['mailcow_cc_username'];
   $mailboxdata = mailbox('get', 'mailbox_details', $username);
 
-  $clientconfigstr = "host=" . urlencode($mailcow_hostname) . "&email=" . urlencode($username) . "&name=" . urlencode($mailboxdata['name']) . "&port=" . urlencode($autodiscover_config['caldav']['port']);
+  $clientconfigstr = "host=" . urlencode($mailcow_hostname) . "&email=" . urlencode($username) . "&name=" . urlencode($mailboxdata['name']) . "&ui=" . urlencode($_SERVER['HTTP_HOST']) . "&port=" . urlencode($autodiscover_config['caldav']['port']);
   if ($autodiscover_config['useEASforOutlook'] == 'yes')
   $clientconfigstr .= "&outlookEAS=1";
   if (file_exists('thunderbird-plugins/version.csv')) {