Create Playwright Testing Package

### Description

I would like a package to help improve Playwright testing. It should set up `wp-env` as a server and use https://mantle.alley.com/docs/models/seeding for database seeding with Mantle's models. The package can make it more performant to run Playwright tests both locally and in GitHub actions.

- [ ] Setup `wp-env`
- [ ] Support seeding and models.
- [ ] Support seeding within Playwright tests.
- [ ] Generate a seeder.

### Use Case

When a developer needs to write Playwright tests for a project it should be easy to start.