Limit the selectable options for php and chroot per client.

install/sql/ispconfig3.sql

interface/lib/classes/tform.inc.php

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

interface/web/client/lib/lang/en_client.lng

interface/web/client/templates/client_edit_limits.htm

interface/web/client/tools.inc.php

interface/web/sites/form/shell_user.tform.php

interface/web/sites/form/web_domain.tform.php