Add accessibility spec (axe-core) to repec

[sandbergja]

What maintenance needs to be done?

Add accessibility tests using the axe-core gem.

Level of urgency

• [ ] High
• [x] Moderate
• [ ] Low

Why is this maintenance needed?

Adding these tests may help us to uncover accessibility issues with the current implementation of this site, and will help us to prevent accessibility regressions in the future.

Acceptance criteria

• [ ] We have accessibility tests for the series listing page
• [ ] We have accessibility tests for a list of papers
• [ ] We have accessibility tests for the administrative forms

Implementation notes, if any

See https://github.com/pulibrary/orangelight/blob/main/spec/features/accessibility_spec.rb for an example