[Design] Template Instance Design - Patterns/Layout Components

[aboydnw]

Context

In the USWDS context, an example full-page layout would be needed to evaluate structural things like site navigation, use of grids, responsiveness, etc.

This is part of a series of tickets to provide guidance to our internal team and, eventually, instance owners. This ticket focuses on layout components like headers and footers.

Related to #998

Acceptance Criteria

• Layout component guidelines are defined in Figma and agreed upon with engineers

Foundational design elements include:

• Headers
• Footers
• Navigation