(Feature request) Should avoid generating inline <script>

[uschwarz]

viewlets.L10nDatepicker writes an inline <script> into the head of the document. This will not work if somebody wants to enable Content-Security-Policy headers (or moves the JS files to the foot/asyncs them/defers them etc.).
Arguably, we can ship out the whole list of dateformats to the client, and the client can inspect lang attributes on body and/or html to pick the right language. Javascript to do that won't depend on the request, so it can be registered and cached by the JS Ressource Registry. The list of enabled languages is short for most people, so there's not much size overhead.