Reference Web UI default styles in layouts

In order to get consistent styling between Designer and Web UI for my layouts, I want Designer to reference existing Web UI styles

When a new layout is created, default web ui styles are referenced in the layout

AC

• Global style file is created in [???] when not existing and a new layout is created
• Global style file contains the default Web UI styles
• Default content for global style file

<!--
***
GLOBAL LAYOUT STYLING SPACE
***
Place custom CSS styles you want to apply globally to your app layouts in this file. 
Studio will reference it in all your layouts and pages, so that they apply no matter which theme users may have chosen.
-->