Handle 500.html error page outside the application

[jibees]

Description

Since openfoodfoundation/openfoodnetwork#9532, we now handle error pages by application directly which allows us to have translated errors pages. But for some critical errors, when application could even no more send any response, there's still a 500.html static page (not translated obviously). This one should be handled here, by ofn-data

Context

Comes from: openfoodfoundation/openfoodnetwork#9532 (comment)