Ref T118, allow to just provide an id (from backend) and set the entity on swift side

* added getDistributorForDbKey
* added fillInMissingAircraftAndLiveryEntities
* fromDbJson function adjusted

src/blackcore/db/modeldatareader.h

@@ -71,6 +71,10 @@ namespace BlackCore
             //! \threadsafe
             BlackMisc::Simulation::CDistributorList getDistributors() const;
 
+            //! Get distributor for id
+            //! \threadsafe
+            BlackMisc::Simulation::CDistributor getDistributorForDbKey(const QString &dbKey) const;
+
             //! Get models
             //! \threadsafe
             BlackMisc::Simulation::CAircraftModelList getModels() const;