Website Accessibility Audit

Copying this from a [Slack conversation](https://chaoss-workspace.slack.com/archives/CV03ATA05/p1691079304945659) so it can be resurfaced when we have a little more capacity.

Quote from @courtneyr-dev:

> Hey folks, I shared https://chaoss.community/kb/metric-event-accessibility%ef%bf%bc/ with the 2 lead organizers of event accessibility for WordPress events. One is blind and uses a screen reader full time. While the content is solid, he indicated the website itself needs some accessibility improvements. Noting he and I both hold leadership roles within the WordPress project, and CHAOSS site is powered by WP.
> We both recommend https://wordpress.org/plugins/accessibility-checker/. This will not magically fix any accessibility issues. It will do a great job of finding what needs to be fixed though, prompting users to update areas for improvement.
> Lack of landmarks, unlabeled links, etc. it should do a good job finding those.
> I've got a busy schedule for the next 6 weeks, but could slot some time in mid-Sept to help audit for these things across the site at that time.

Huge thank you to @courtneyr-dev for bringing this up! 🤩 Let's take a look at this again in September.

cc @klumb @germonprez