[ticket/12646] Add data-# attribute to breadcrumb links

https://tracker.phpbb.com/browse/PHPBB3-12646

PHPBB3-12646
I agree with the first remark.

But the second would only be useful I think if we add a core event to https://github.com/phpbb/phpbb/blob/develop-ascraeus/phpBB/includes/functions_display.php#L664