Create an `initList` for the Propgator

In view of the latest development for external surfaces, the Propagator should have a initList which is called before navigation::status and actionList.

It can share the implementation with the AbortList in a common ConditionList implementation, different from the ActionList the InitList and AbortList are not producing result output.

Also the KalmanActor would then be split in a KalmanInitialiser and KalmanActor which allows to inject External surfaces at the very start of the propagation flow, i.e. external surfaces are taken into account at the first navigation call and not at the first actionList call.