Support RFC 9110 HTTP status code constants

[mbeijen]

DRF has constants for HTTP status codes. They do not reflect the naming from rfc9110 which updates some earlier terms; see https://www.rfc-editor.org/rfc/rfc9110.html#name-changes-from-rfc-7231

RFC 9110 has been accepted as an Internet Standard since June 2022. It would be great if Django REST Framework would use the updated naming. In order not to break existing code the old constants should also be preserved.