Fix EZP-21747: Translated name should be accessible from ContentInfo

https://jira.ez.no/browse/EZP-21747

Follow up of [EZP-21531](https://jira.ez.no/browse/EZP-21531).
In many cases you can only have ContentInfo object exposed, so
`ez_content_name()` Twig function should accept Content or ContentInfo
objects to get name from.