i18n for new Web UI

Provide i18n helpers and/or elements for usage in client applications.
This requires not only support for integration with the current JSF app and its message bundles but also for "standalone" webapps which will need to handle loading the bundles on their own.
Translation of messages should still be handled with CrowdIn thus the import/export jobs will need to be update to handle the new web applications and elements as well.