Spike: Introduce react-testing-library

[jpuzz0]

Describe the issue. What is the expected and unexpected behavior?
Provide an additional means of unit testing for contributors which focuses less on implementation details and more on how users interact with components.

[jpuzz0]

This story resulted in a presentation to the patternfly team during one of our retrospectives which cited the packages involved, a sample test, and the main differences between RTL and Enzyme.

Next steps will be to create a best practices document (have this reviewed and published to PatternFly for Developers) and open a PR with the initial setup + 1 or more tests using the new libraries.