Global function fields: basic classes

[kwankyu]

This is part of the meta-ticket #22982.

The goal of the present ticket is to trim the existing code and add several classes that are now just stubs, to prepare for the next step.

CC: @johanrosenkilde

Component: algebra

Author: Kwankyu Lee

Branch/Commit: d5ad194

Reviewer: Travis Scrimshaw

Issue created by migration from https://trac.sagemath.org/ticket/24591

[kwankyu]

Branch: u/klee/24591

[sagetrac-git]

Commit: 3c46c03

[sagetrac-git]

Branch pushed to git repo; I updated commit sha1. Last 10 new commits:

3b37339	Add back proof=True to _factor method
daed064	Remove differentials code
07abebb	Remove differentials code
639c2fd	Remove differentials docstrings
836ed53	Remove divisors code
8cf530f	Remove places and valuation code
895572c	Remove ideals code
f4bc048	Rename element ideal order files
50efcbb	Rename ideal order element modules
3c46c03	Remove orders code

[kwankyu]

Author: Kwankyu Lee

[sagetrac-git]

Changed commit from 3c46c03 to cc3b897

[sagetrac-git]

Branch pushed to git repo; I updated commit sha1. New commits:

cc3b897

Small trimmings

[sagetrac-git]

Branch pushed to git repo; I updated commit sha1. New commits:

84acd60

Merge develop