The shared `MGLMapboxEvents` now owns the only instance of `MGLMetricsLocationManager`. It also owns a `MGLMapboxEventsData` object, to which all user-specific data has been relegated. This object can be built up and torn down on the fly, whenever the opt-out preference is toggled. `MGLMapboxEvents` has also given up knowledge of the access token and now queries `MGLAccountManager` for that information, which `MGLMapView` keeps up-to-date.