Add out of the box support for a11y tests

[yannbf]

Closes #

What I did

Before:

• Users had to install axe-playwright and write code from a recipe with test-runner hooks
• It was easy to miss passing the story context to the a11y report and therefore there would be a mismatch between the addon a11y settings and the a11y test in the test-runner
• Logs weren't attached to the test result
• Logs took a lot of space and were hard to parse
  

After:

• No need for extra dependencies, works out of the box
• Respects the a11y.test parameter as per the docs
• Error logs are attached to the test result
• Logs are formatted and easy to parse
• There is a link to debug directly in the a11y panel
  

Additionally, there is the a11y.test: 'todo' mode, where the tests pass but there are shorter logs in the report.
We should discuss how this should work. Unfortunately the logs aren't attached to the report in this mode.

Checklist for Contributors

Manual testing

This section is mandatory for all contributions. If you believe no manual test is necessary, please state so explicitly. Thanks!

Documentation

• Add or update documentation reflecting your changes in this repository
• Request documentation updates in the test-runner docs website

Checklist for Maintainers

• Make sure this PR contains one of the labels below:

  Available labels

  • skip-release: Skip any releases, e.g., documentation only changes, CI config etc.
  • patch: Upgrade patch version (e.g. 0.0.x)
  • minor: Upgrade patch version (e.g. 0.x.0)
  • major: Upgrade patch version (e.g. x.0.0)

[ghengeveld]

LGTM

[yannbf]

smoke test -> render test
add prefix to message with story title > story name