Add temporary date format helper for AU launch

So it turns out there is a bug related to AU timezones in are underlying time date library `Joda DateTime` see this thread for more detail: https://github.com/JodaOrg/joda-time/issues/175

This introduces a temporary `AuFriendlyFormat` helper as a hack around the solution for the AU launch until we can solve more elegantly.

I am only applying this to the main timestamp on content pages.

/cc @rich-nguyen