Add testing in particular accessibility testing

[dmundra]

Overview

As an accessibility expert, I want to have automatic accessibility testing configured, so that I can ensure all our changes are meeting our accessibility requirements

Q: Cypress + axe or something else? Playwright + axe?

Background

Previous site has had pa11y-ci and cypress tests with axe for accessibility testing.

References

No response

Acceptance Criteria

• Testing framework is selected and installed
• Accessibility tests are created for all public pages
• Accessibility tests run automatically on every pull request