Validation Summary for Optimizely Forms

I have seen requests for a method to implement a Validation Summary for Optimizely Forms, and I dealt with one myself. If you're not familiar with the idea, a Validation Summary includes all the validation messages for form fields in a summary section for easy review. This is typically found at the top of the form after you try to submit. There is no option for this functionality out of the box with Optimizely so I put it together.