Merge branch '5626-tools' into 'stable-3.1'

interface/web/tools/form/interface_settings.tform.php

interface/web/tools/form/user_settings.tform.php

interface/web/tools/interface_settings.php

interface/web/tools/lib/lang/ar_interface.lng

interface/web/tools/lib/lang/ar_usersettings.lng

interface/web/tools/lib/lang/bg_interface.lng

interface/web/tools/lib/lang/bg_usersettings.lng

interface/web/tools/lib/lang/br_interface.lng

interface/web/tools/lib/lang/br_usersettings.lng

interface/web/tools/lib/lang/ca_interface.lng

interface/web/tools/lib/lang/ca_usersettings.lng

interface/web/tools/lib/lang/cz_interface.lng

interface/web/tools/lib/lang/cz_usersettings.lng

interface/web/tools/lib/lang/de_interface.lng

interface/web/tools/lib/lang/de_usersettings.lng

interface/web/tools/lib/lang/dk_interface.lng

interface/web/tools/lib/lang/dk_usersettings.lng

interface/web/tools/lib/lang/el_interface.lng

interface/web/tools/lib/lang/el_usersettings.lng

interface/web/tools/lib/lang/en_interface.lng