Increased styling customization options

[maxine]

Problem Description

@NUKnightLab has its own style guide, and we would like to use it to style our Library instance and then use select default Library styles such as the grid system alongside the custom styles.

Right now, a way to achieve this would be to create an empty file for each file in the styles directory in the custom directory (ex: custom/styles/core/_furniture.scss to override styles/core/_furniture.scss) and then selectively copy-paste Library styles we want to keep into those custom files.

Feature

It would be nice to have an easier way to customize Library beyond fonts and colors. One way to do this would be to create more modular SCSS files per feature/component that can be selectively imported. Happy to discuss other implementations in this thread!