Add support for NN startNavigationSession/stopNavigationSession methods

[kried]

Description

Closes NAVIOS-983

Implemented logic is:

• iOS SDK calls startNavigationSession if the session was not started yet, and either an instance of PassiveLocationManager is created (free drive) or the callback of Navigator.setRoutesData was called (active guidance)
• it calls stopNavigationSession when no more session running (could be deinitialization of PassiveLocationManager or Navigator.setRoutesData(null))
• it calls storeNavigationSession before switching to offline or switching back to online. And SDK calls restoreNavigationSessionForState when switching finished

[Udumft]

What if we hook NavigationSessionManager to the Navigator lifecycle? It uses weak references for shared instance and thus we can detect when it is created and deallocated. Since start/stop calls seems to directly match NN Navigator lifetime it seems correct. Also, this will also save us from spreading this start/stop logic across Navigator consumers.

[kried]

I agree It would be much easier.
But it could lead to incorrect Telemetry reports. If start is called before the route is set to the NN Navigator, NN would first report fake navigation.freeDrive.start and navigation.freeDrive.stop events. Because NN doesn't know that navigator was created for active navigation until it finishes setRoutesData

So we later won't be able to differentiate actual free drive events from these fake events.

[Udumft]

We can detect this logic by probing Navigator.updateLocation(_:completion:) and Navigator.setRoutes. If location is updated before route is set - that's a free drive. If routes are set - we are entering AG and should end FD if any.

[kried]

We discussed that with the latest NN version, the NN stores the last reported location and reports free drive after Navigator.setRoutes(nil) even without the next call of Navigator.updateLocation(_:completion:).
So we need to stop the session if there are no free drive running in order to avoid fake free drive events.