Cyclic fetch domain states

[jannikbecher]

currently when in operational there is no way to figure out if the cyclic task is running.
Furthermore it should be controlled, that each slaves is in OP state

[jannikbecher]

maybe add a new state "unhealthy" in this state the master has some hardware problems, but is still in operational state

[jannikbecher]

add new poll interval in operational state :check_health_interval
when health is not good for a specific time it should transition to unhealthy