Create Styles at a Global Scale

[rgauss]

Description

As a developer of the OSCAL Viewer, I would like styles to be declared at a global level for easy reusability among components.

Acceptance Criteria

• A strategy is proposed for reusable styles at a global scale
• An implementation of styles at a global scale is made follow the proposed strategy
  • This is only to the degree of styles defined in the style guide today

Proposed Solution

A top-level folder is created to contain styles at a global scale for components to reuse.

Additional Notes

No response

### Tasks
- [ ] https://github.com/EasyDynamics/oscal-react-library/issues/773
- [ ] https://github.com/EasyDynamics/oscal-react-library/issues/774
- [ ] https://github.com/EasyDynamics/oscal-react-library/issues/775

Implementation

• [ ] I can (or plan to) submit a pull request to implement this
• [ ] Implementing this may result in a breaking change

[rgauss]

Originally raised by @Bronstrom