Adds a FAQ on our new wrapper

[rebeccabilbro]

This small PR adds an additional FAQ to help direct inquiries to our wrapper documentation when they are using third-party estimators with Yellowbrick.

CHECKLIST

• Is the commit message formatted correctly?
• Have you noted the new functionality/bugfix in the release notes of the next release?
• Included a sample plot to visually illustrate your changes?
• Do all of your functions and methods have docstrings?
• Have you added/updated unit tests where appropriate?
• Have you updated the baseline images if necessary?
• Have you run the unit tests using pytest?
• Is your code style correct (are you using PEP8, pyflakes)?
• Have you documented your new feature/functionality in the docs?
• Have you built the docs using make html?

[bbengfort]

Awesome, thanks for adding this to the FAQ!