Only allow code from certain packages to be used in some paths

[ruudk]

It would be great if I could configure the analyzer like this:

$config->onlyAllowPackagesInPaths(
    [
        'phpstan/phpstan',
    ],
    [
        __DIR__ . '/src/PHPStan/Collector/SomeCollector.php',
    ],
);

It might be specific to my project where I have an application that also ships with a PHPStan Collector. The PHPStan Collector can use code from the PHPStan library. But the rest of the application should not use it. I could solve it by extracting the Collector to a separate package, but that's a lot of extra work for no real benefit.

But it might be that this could apply to more projects too.