Add WAF Captcha as an option for Waiting Room SPA entry

[Jim Thario]

Describe the feature you'd like
Include an example of integrating WAF Captcha with the CF/S3 distribution serving the waiting room single-page application as an additional control to entry.

Additional context
https://aws.amazon.com/about-aws/whats-new/2022/06/aws-waf-captcha-generally-available/
https://docs.aws.amazon.com/waf/latest/developerguide/waf-captcha.html