QmlProfiler: Move parts of model manager and trace file to Timeline

This way we can use the trace file loading and saving mechanism for
other profilers.

Change-Id: I98ec1cdde6f7abcea152cabf72e64d4e696dfa59
Reviewed-by: Tobias Hunger <tobias.hunger@qt.io>

src/plugins/qmlprofiler/qmlprofilerstatisticsmodel.h

@@ -152,7 +152,6 @@ private:
     void loadEvent(const QmlEvent &event, const QmlEventType &type);
     void finalize();
 
-    void modelManagerStateChanged();
     void typeDetailsChanged(int typeIndex);
     void notesChanged(int typeIndex);