Make robot tests more stable/robust

[gforcada]

By changing selenium for playwright 🎭 🎉

There are plenty of factors:

• robot tests based on selenium have been famously flaky locally, but specially, in Jenkins
• playwright promises much better stability by providing tight integration with the browser is being orchestrated, rather than being left to the user to provide the required, browser and driver integration
• and foremost there is robotframework-browser an integration layer between playwright and robotframework

Last point mostly means (hopefully 🤞🏾 🍀) that we don't have to rewrite our existing tests to new syntax.

The @plone/volto-team team is using Cypress with great success.

Mockup is using jest as a testing framework, not sure if they are planning to use Cypress/playwright at any point in time.

At Alpine City Sprint it was discussed that this might be a good way forward. For the unlucky ones that could not made it for any reason to the sprint, please speak/write up on the comments ⌨️ 🗨️ !

[gforcada]

See #3813