Make the plugin.Services class available at the base module level for easier typing

[jenstroeger]

Hello, thank you for this plugin! One minor issue with using typed code on my end is that I have to use

def test_function(docker_services: pytest_docker.plugin.Services) -> None:
    ...

because the Services class itself wasn’t imported into the main module. This change adds the class name which should make typing a little easier…

[Copilot]

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