fix coercion from libgap's finite fields, use libgap in sage/rings/finite_rings #34770
Description
implement coercion from libgap's finite fields, to fix e.g.
sage: F=GF(25)
sage: F(libgap.Z(25)^3)
---------------------------------------------------------------------------
TypeError Traceback (most recent call last)
...
TypeError: unable to coerce <class 'sage.libs.gap.element.GapElement_FiniteField'>
With the ticket branch, this works:
sage: F=GF(25)
sage: F(libgap.Z(25)^3)
4*z2 + 3
As well, we switch to use libgap instead of pexpect GAP - internally
in the affected files. This is a part of #26902
Component: number theory
Author: Dima Pasechnik
Branch/Commit: 6e5ea79
Reviewer: Matthias Koeppe
Issue created by migration from https://trac.sagemath.org/ticket/34770