Update documentation site Shadow page content to use Utility page template

[sarinapadilla]

Request Description

This change request is update the Shadow page on the NCIDS from only having basic information about shadow tokens to using our Utility page template.

• [ ] IA/Design updates to the Shadow doc site page with full instructions on use
• [ ] Design updates to the community Figma
• [x] Developer updates to the code to adopt Shadow within the NCIDS

Important Notes

• The content on this page will use the utility page template outlined in #1593.
• Utilities spreadsheet
• USWDS Shadow page

What's the expected change?

• The Doc Site is updated to show users how to fully use shadow utilities/tokens on the NCIDS Doc Site without pointing to USWDS
  • The existing tokens will be included on the page
• The community Figma file will be updated to include shadow utilities/tokens
• The NCIDS code will be updated to fully adopt shadow utilities/tokens

What's the current functionality?

• The NCIDS has some information on Shadow tokens and updates from USWDS.

Related Tickets

• 1593

[karlikpj]

Approach would be to use the box-model demonstration component as its look and columns match that of outline or border.