Add initial upstream integration test
    
    Re-use the test skeleton from cockpit. Just run a single integration
    test for now, until we make them properly @nondestructive upstream [1].
    
    Run chromium and the test directly on the test bed. For cockpit-podman
    tests it's not practical to run them in a cockpit/tasks podman
    container, as that container interferes too much with the tests.
    
    [1] https://github.com/cockpit-project/cockpit-podman/pull/356