Partition orderings

[tscrim]

On #13605, the notion of overriding the default order on partitions was introduced. However due to speed regressions (#13991), we needed to push the part of #13605 that converted Partitions* into subclasses of UniqueRepresentation. This ticket is for separating out ordering on partitions.

For the current discussion see:

• Partition options and cleanup partitions documentation #13605
• https://groups.google.com/forum/?fromgroups=#!topic/sage-combinat-devel/40YJR38-VU0
• https://groups.google.com/forum/?fromgroups=#!topic/sage-combinat-devel/zZmLHk8g4Ew

Depends on #13605

CC: @AndrewAtLarge @sagetrac-sage-combinat

Component: combinatorics

Keywords: partitions, ordering

Author: Travis Scrimshaw

Issue created by migration from https://trac.sagemath.org/ticket/14013