Add a Symfony recipe

[tacman]

When I install the bundle (which really be called SmokeTestingBundle or smoke-test-bundle, for consistence with the rest of the ecosystem), I'd like to have that first test automatically created, and a phpunit.xml or phpunit.xml.dist file created.

Alternatively, if the installation instructions are in a bash block, it can be and easy cut and paste to install. This is what I do.

composer require --dev pierstoval/smoke-testing
cat <<'EOF' > tests/AllRoutesTest.php
<?php

namespace App\Tests;
use Pierstoval\SmokeTesting\SmokeTestStaticRoutes;

class AllRoutesTest extends SmokeTestStaticRoutes
{
    // That's all!
}
EOF

vendor/bin/phpunit

[Pierstoval]

The PHPUnit configuration will automatically be added thanks to Symfony's recipe.

Also, I'm not sure to be ok with a Flex recipe right now, since the project is still in the "Pierstoval" namespace. I'd prefer to move it to the "Orbitale one" (which corresponds to my open source projects, ant not only my experiments) beforehand. I don't want my nickname to be stored in Symfony's code, even the "contrib" recipes.
Since there were a very few amount of users of this library, I didn't think it would be worth changing the namespace, but maybe more users would help convince me to do it :)