add 2 new executable i18n scripts:

/usr/bin/i18n - takes a (js) page & key, provides a translation value. Used in forthcoming openvpn openvpn_upload_client.sh which has strings set in a shell environment pushed to javascript

/usr/bin/i18n-menu - takes a fully formed uci page (gargoyle.display.status_openvpn_connections) and provides a translation value. Used when a feature is activated & a menu item becomes active.