Check for invalid dates at actor/event participation
Search invalid dates in combination of events and actors and return the participation links e.g. an attending person was born after the event ended
Because of the many possible combinations: an actor, an event and a particpations can have their own dates (or even timespan as dates) this check function will not cover all possibilites in this version.
Maybe we will expand it in a future version but for now we implent most of them and wait for feedback from projects.