introduce a variable which skips systemd-sleep services
    
    The automated TC contains a phase where services systemd-hybrid-sleep
    and systemd-hibernate are started for testing purposes. Unfortunately,
    running these services had real consequences on machines in certain
    environments where the TC was executed (for example: machines became
    unresponsive).
    To have some control of the situation, a new environment variable was
    introduced. It is called REAL_SCENARIOS and it can avoid the situation
    when set to false. Default value of the variable is true which means
    that above-mentioned services will be executed.