[FEATURE] Add rule to check if service is private

[sabbelasichon]

In order to have something similar to https://github.com/phpstan/phpstan-symfony/blob/1.4.x/src/Rules/Symfony/ContainerInterfacePrivateServiceRule.php in the repository

So if you have calls inside your code to get private services from the container (Service Locator Pattern) you will get a phpstan error.