Add playground website

[ijpatricio]

To start adding Operations and confirmations, we are better off with a own playground website.
Instead of asking, I promptly prepared a suggestion, which you can discard, of course.

Possibilities

We can:

• Have a controlled environment to make scenarios, by controlling a website HTML and JS.
• Potentially, in an isolated pipeline, we can install the package on the playground app (composer path), and assert the good behavior in a consumer scenario.

What was done

In the folder "playground" (gitattribute: export-ignore), There's a "laravel new" installation, without any starter kit.

In the playground, after a clean installation:

• Committed the .env, as it's a dummy thing to be there.
• Cleaned the welcome.blade.php view to a simple Title and body: Pest Browser Testing
• All the rest is vanilla Laravel, and all .gitignore were maintained, except for .env

In the core repo:

• Configured the Webserver that Playwright will handle in the background
• Config for host and port and baseURL, so it can be defined in a single source of truth
• Port 9357 to resemble PEST // 9 is the most similar with P, then 3E 5S 7T

Conclusion

1. We can now write a tests like so. This one is added already:

it('can visit our website', function () {
    visit('/')
        ->toHaveTitle('Pest Browser Testing');
});

All green.

2. I didn't do the "Playground as consumer" thing. Wanted your opinion, before doing it in a separate PR.

[ijpatricio]

Revisited and edited original post after a few QOL improvements