Standard accessibility checks

[mark-wiemer]

At my job at Microsoft, we use Playwright and axe-core to automatically check for simple accessibility (a11y) issues in our website. I'm happy to work to integrate similar functionality here.

That said, we can also manually use Accessibility Insights for Web to do a thorough accessibility review every ~6 months to ensure new features haven't ruined a11y of a given page or the site as a whole

[wsor4035]

initial code merged in #142, still needs "errors" fixed and ci job added