[2.x] Add the ability to publish and use test stubs

[michaelr0]

Q	A
Bug fix?	no
New feature?	yes
Fixed tickets	0

Similar to pestphp/pest#596 this PR aims to allow the following Pest Tests stubs to be published into a Laravel project and modified for each specific project's requirements:

• Browser.php
• Dataset.php
• Feature.php
• Unit.php

The adjusted logic generates an outcome similar to the Laravel's existing artisan stub:publish and artisan make:test commands.

To publish the Pest stubs, the new artisan pest:publish command can be used, the stubs will be published as:

• pest.browser.stub
• pest.dataset.stub
• pest.feature.stub
• pest.unit.stub

These will then be found in the stubs directory on the project root.

The command behaves similarly to artisan stub:publish and has the --existing and --force options available for use.

artisan pest:dataset and artisan pest:test will generate files from the published stubs if they are present, otherwise the ones from the phppest/pest package will be used.

[jonjakoblich]

I was just looking for this exact feature!