PositionMonitoring can now monitor multiple zones per monitoringRequest

tracking behaviour implemented
  PositionEvents are stored and associated to the respective monitoringRequest
  queryRequest/queryResponse can be handled
added fake-functionality for position-scaling for frontend-app demonstrator
removed side-effect in function PositionMonitoring.isEntryNotification
data model changes
  EventFilterCondition.positionConditionCell becomes a map
  MonitoringRequest.frameId becomes a list
  EventFilterCondition.positionConditionCellId got removed
still open
 remove side-effect of the scale_position_frontend_app-Function