Merge branch '4127-default-country' into 'develop'

Add a default_country config option

Closes #4127

See merge request ispconfig/ispconfig3!1618

Author: Till Brehm

interface/web/client/form/client.tform.php

@@ -318,7 +318,7 @@
 		'country' => array (
 			'datatype' => 'VARCHAR',
 			'formtype' => 'SELECT',
-			'default' => (isset($conf['language']) ? strtoupper($conf['language']) : ''),
+                       'default' => (isset($conf['default_country'])) ? strtoupper($conf['default_country']) : ((isset($conf['language'])) ? strtoupper($conf['language']) : ''),
 			'datasource' => array (  'type'          => 'SQL',
 				'querystring'   => 'SELECT iso,printable_name FROM country ORDER BY printable_name ASC',
 				'keyfield'      => 'iso',