Add PyLong_AsNativeBytes and PyLong_FromNativeBytes to the stable ABI

[zooba]

Feature or enhancement

As was originally planned. These have been out in 3.13, and while it is most prominently used in Cython, has been broadly validated to be safe enough for stable ABI addition.

Linked PRs

• gh-132639: Adds PyLong_AsNativeBytes, PyLong_FromNativeBytes and PyLong_FromUnsignedNativeBytes to the limited API #132640