Expose battery monitoring

[frederoni]

This PR exposes isMonitoringBatteryState so a user can disable it and use their own desired accuracy.

@bsudekum @ericrwolfe 👀

[bsudekum]

@frederoni where exactly can they disable it?

[frederoni]

On the location manager before you start navigation

let locationManager = MyLocationManager()
locationManager.isMonitoringBatteryState = false
…

or reaching through the navigation and route controller

navigationViewController.routeController.locationManager.isMonitoringBatteryState = false

[bsudekum]

I think we should rethink this. If the goal is to have control over the kCLLocationAccuracyBestForNavigation vs kCLLocationAccuracyBest, we should expose that. Battery monitoring should always be enabled for telemetry purposes.

[frederoni]

Made a few changes here. We always observe the battery state but only update the desired accuracy when automaticallyUpdatesDesiredAccuracy is set to true.

However, the actual battery monitoring is something that the RouteController is responsible for.
This PR won't have any impact on telemetry or anything else by default.

[bsudekum]

Nice, this looks great.