sage.rings.integer, rational: Remove compile-time dependency on cypari2 and flint #30022
Description
Functions such as set_from_pari_gen should probably be moved to sage.libs.pari.convert_sage.
The compile-time dependency on sage.libs.flint.ulong_extras is for the use of n_factor.
Component: refactoring
Author: Matthias Koeppe, Jonathan Kliem
Branch/Commit: b4477da
Reviewer: Jonathan Kliem, Matthias Koeppe
Issue created by migration from https://trac.sagemath.org/ticket/30022