Added: SSH authentication option (password, key, both)

install/tpl/system.ini.master

interface/web/admin/form/system_config.tform.php

interface/web/admin/lib/lang/de_system_config.lng

interface/web/admin/lib/lang/en_system_config.lng

interface/web/admin/templates/system_config_misc_edit.htm

interface/web/sites/shell_user_edit.php

interface/web/sites/templates/shell_user_edit.htm