Toggle authors in alphabetical order ascending or descending

[rkotze]

Summary

Provide an action to toggle the authors between ascending or descending alphabetical order.

This would apply to selected, unselected, and repository authors.

Motivation

Provide users a choice to order co-authors and to make it easy to scan the code.

Tech notes

A good place to start looking is in this file: https://github.com/rkotze/git-mob-vs-code/blob/master/src/mob-authors.js