Implement *deactivate-catchall*-feature, refs #fixes 1114

Signed-off-by: Arnold Bechtoldt <mail@arnoldbechtoldt.com>

actions/admin/settings/150.mail.php

@@ -99,6 +99,14 @@ return array(
 					'type' => 'hidden',
 					'default' => 0,
 					),
+				'system_catchall_enabled' => array(
+					'label' => $lng['serversettings']['catchall_enabled'],
+					'settinggroup' => 'catchall',
+					'varname' => 'catchall_enabled',
+					'type' => 'bool',
+					'default' => true,
+					'save_method' => 'storeSettingResetCatchall',
+					),
 				),
 			),
 		),