Query parameter to list endpoints newest-to-oldest

[svix-andor]

The overall pagination is still done first-to-last, but within a page results are listed last-to-first.

Builds on top of #812

[tasn]

I think it's fine. Just making sure: you have the tests to ensure this works + tests to verify you haven't broken the ordering for anything else?

[svix-andor]

I believe so. The again-generic apply_pagination and listing_response is only used for Endpoint listing, the remainders still use the direction specific variant (which I intend to remove once all have bidirectional listing).