Add playwright test to cardano-wasm to ensure it works in browsers

[palas]

Changelog

- description: |
    Added playwright test to `cardano-wasm` and `.#playwright` development shell
  type:
  - test
  projects:
  - cardano-wasm

Context

One of the objectives of input-output-hk/cardano-node-wiki#75 is to ensure that the JavaScript library can be used easily in vanilla JS (from the browser). This PR adds a playwright test that verifies the example in the example folder outputs what is expected when run exclusively on the browser.

As part of this work, this PR also adds a development shell nix develop .#playwright that includes the python server and the playwright setup for facilitating testing.

How to trust this PR

It is a test, so it passing it already gives a lot of assurance. You could modify the test to verify it indeed fails. And I would check that the code structure is appropriate and that there is no dead code. You can also check that the shell works for you, but hydra should do that automatically.

Checklist

• Commit sequence broadly makes sense and commits have useful messages
• New tests are added if needed and existing tests are updated. See Running tests for more details
• Self-reviewed the diff

[Jimbo4350]

LGTM however I would have a look at Quickstrom as well.