[joss][tests] Use playwright for testing multiple browsers

[sneakers-the-rat]

Part of: openjournals/joss-reviews#6336

• These changes fix: [joss][tests] Test run failure - before hook times out #18
• npm test ran with full success.

• I implemented tests for the changes I made OR
• These changes do not require tests because these changes are adding test cases

Problem

Puppeteer is made for chromium-browsers only. Google is trying to own the web via chrome. Part of the problem is a constant shifting target that breaks other browsers. Ergo testing against other browsers is important for a free web.

This PR

• Switch puppeteer with playwright - which is developed by the same team as puppeteer for testing across browsers
• Adds setup and teardown for http server so tests run.

Split into two commits so it's easier to see changes - first commit is just substantive changes, and second commit is linting.

Really simple changes, just wrap tests in an additional forEach + describe block that tests with a given browser as described in the mocha docs. Use mocha global fixtures again as described in the docs

[katjaq]

Thank you so much for this PR @sneakers-the-rat ! That's a fantastic upgrade ⭐

Also, thank you for all your other comments you had during the review process – we are working on them – and also for your linked discussion on mastodon! 😍 ❤️ So kind! We would be super happy about the PR you describe there. This is an amazing review process – we learn so much from you. Thank you from all 3 of us! <3

[sneakers-the-rat]

Fabulous :) glad it's helpful. I'm not done with my review yet! just need to find time to finish it. obvi it looks good to me but i will at least show a demo of webpacking it into a single page and see how else i can be useful <3