Review 5.4 Changes

[bhubbard]

Review how 5.4 changes can be used to improve our navwalker.

WordPress 5.4 Introduces new hooks to add custom fields to menu items

[IanDelMar]

I have looked into this and while it would be useful in terms how easily one can configure menu items, when using custom fields you add database calls reducing the performance of the nav walker (without caching). If the first outweighs the latter WP Bootstrap Navwalker should definitely use custom fields, if not one should forget about the custom fields. Custom fields also add to lower maintainability (set up and save custom fields, and so on). My preference: no custom fields.