Improve annotations to work in both vertical and horizontal plots (#9154)

* Move enums to RiaPlotDefines.h
* Add support for formation names shading in horizontal plots
* Refactor line property code
* modernize code

ApplicationLibCode/UserInterface/RiuSummaryQtChartsPlot.h

@@ -50,6 +50,7 @@ public:
 
     void useTimeBasedTimeAxis() override;
 
+    void clearAnnotationObjects() override;
     void updateAnnotationObjects( RimPlotAxisPropertiesInterface* axisProperties ) override;
 
     RiuPlotWidget* plotWidget() const override;