Realization in Ensemble RFT-plot hover info + refactoring of point tracker functionality

* Add realization number to mouse over text for Ensemble RFT

* Refactor Curve Info Text Provider functionality

- Refactor provider implementation, to separate RiuWellLogTrack from the point tracker and text provider.
- Move creating of point tracker outside of RiuWellLogTrack.
- Makes it possible to override/write new CurveInfoTextProvider implementation when needed.

* Add guards for nullptr

ApplicationLibCode/ProjectDataModel/RimDepthTrackPlot.h

@@ -27,6 +27,8 @@
 #include "RimPlot.h"
 #include "RimPlotWindow.h"
 
+#include "RiuPlotCurveInfoTextProvider.h"
+
 #include "cafAppEnum.h"
 #include "cafPdmChildArrayField.h"
 #include "cafPdmChildField.h"
@@ -197,6 +199,9 @@ protected:
     void                 updatePlots();
     caf::PdmFieldHandle* userDescriptionField() override;
 
+    void                                  createAndSetCurveTextProvider( RimWellLogTrack* track );
+    virtual RiuPlotCurveInfoTextProvider* curveTextProvider() const;
+
 private:
     void cleanupBeforeClose();
     void updateSubPlotNames();