Add Playwright tests

[BrtqKr]

Details

We wanted to reduce number of regressions occurring after the contributions, so I've done a setup for playwright e2e tests for web.

This PR includes:

• constants restructuring (everything is wired up to the example, so we can keep this consistent)
• playwright setup for testing
• basic tests for styling and input-related actions (cut, paste, copy, cursor change etc)
• CI action for running those tests

Related Issues

GH_LINK

Manual Tests

cd WebExample
yarn test

Linked PRs