Bug 31383: Fix URLs on staff AC detail view

Bug 31383: Fix URLs on staff AC detail view

No real need anymore for showing a Default and Current language link.
They could be made with the language parameter (not lang), but just
changing the language allows you to test easily.
Would you really like to see Default when you added content for all
enabled languages? You can still add language=default to the URL.

Test plan:
Test the page URLs. Experiment with changing language in the regular
way and via URL parameter.

Signed-off-by: Marcel de Rooy <m.de.rooy@rijksmuseum.nl>
Signed-off-by: Martin Renvoize <martin.renvoize@ptfs-europe.com>
Signed-off-by: Tomas Cohen Arazi <tomascohen@theke.io>