USWDS - Input prefix/suffix: Ornaments for text inputs

[jaredcunha]

Description

For issue #3939

Adds prefixes or suffixes to text fields.

Additional information

• Supports either icons or text
• Creates focus state when clicking prefix/suffix (supported by usability research)

Before you hit Submit, make sure you’ve done whichever of these applies to you:

• Follow the 18F Front End Coding Style Guide and Accessibility Guide.
• Run npm test and make sure the tests for the files you have changed have passed.
• Run your code through HTML_CodeSniffer and make sure it’s error free.
• Title your pull request using this format: [Website] - [UI component]: Brief statement describing what this pull request solves.

[jaredcunha]

@thisisdano do you have thoughts on what should show for the documentation site? Was thinking about using the two options above.