Consolidate menu macro in main template

Problem/Motivation

Every time something changes in the menu templates, it usually has to be propagated to all three templates:

menu.html.twig
menu--main.html.twig
menu--account.html.twig

The code can easily be copy and pasted, but that is still essentially duplicating code and continues to leave an opportunity for human error to occur.

Proposed resolution

Consolidate the menu macro in main.html.twig and use {% extends "menu.html.twig" %} in menu--main.html.twig and menu--account.html.twig.

Refactor the macro in menu.html.twig to pass classes for the <ul> element.