Add How to Swap Content Components documentation

[danbrady]

Duplicate check

• [X] I've searched for any related issues and avoided creating a duplicate issue.

This update is for:

Other

What is the name?

Applies to multiple components

What is the nature of this update?

• [X] How to build this component/pattern
• [ ] When to use this component/pattern
• [ ] When to use something else
• [ ] Usability guidance
• [ ] Accessibility considerations
• [ ] Content considerations
• [ ] Implementation
• [ ] Package information
• [ ] Addition to Forms Library documentation
• [ ] Update to existing Forms Library documentation

What problem does this solve?

Many VADS components have the ability to swap in another component or a custom content component that would be local in a designers Figma file. We should add a page to describe what that means and how to do it for any folks that may not have that experience.

Additional Context

TBD: Should this be in Figma? Doc site? Both?

[caw310]

Hey team! Please add your planning poker estimate with Zenhub @babsdenney @danbrady @LWWright7