A11y audit & update scorecard after v5

[nicolethoen]

Make progress toward: https://github.com/patternfly/patternfly-org/issues/2919

Once v5 is live, now that we are publishing org's a11y scorecard, we are due for an updated scorecard and a11y audit.

• [ ] update the a11y config to make sure it is optimized for the new IA
• [ ] note all a11y violations, address low hanging fruit, document further work needed
• [ ] fill out new scorecard and update the website page to reflect new report