Trac #27366: Polyhedron.affine_hull: more output options

At the moment when calling `.affine_hull`, either the polyhedron or the
affine map can be returned. If both needed, parts need to be recomputed,
so we extend the parameters to allow returning both at the same time.

Moreover, we also allow to additionally return the section map, i.e.,
the right inverse of the projection map. This is a preparation for
#27365 and #31659.

URL: https://trac.sagemath.org/27366
Reported by: dkrenn
Ticket author(s): Daniel Krenn, Matthias Koeppe, Jonathan Kliem
Reviewer(s): Matthias Koeppe, Jonathan Kliem