Components: Standardize JS - Menu

Problem/Motivation

We would like to standardize the structure and formats around our components with JavaScript

The menu component is complex containing several files
- Menu Aria Controls
- Menu Mobile Controls
- Menu (core file)

Remaining tasks

- Breakout functions
- Include docblocks for each new function
- Drupal specific elements will occur inside the attached behaviour
- Should leverage only vanilla JS
- Review naming conventions, specifically event handling
- Should leverage `let` or `const` instead of `var`