Sketcher: DrawSketchHandler draw multiple edit curves

=====================================================

Extension of the framework to draw an arbitrary curve in draw sketch handlers, so that
a plurality of curves can be handled.

DrawSketchHandler is extended to additionally offer drawing several curves:
- void drawEdit(const std::list<std::vector<Base::Vector2d>> &list);
- void drawEdit(const std::vector<Part::Geometry *> &geometries);

A new class, CurveConverter, enables to convert individual Part::Geometry or vectors of them
to appropriate vectors or list of vectors of Vector2d representing the curves. This can be
used in a specific DrawSketchHandler to combine Part::Geometries and arbritary curves.

src/Mod/Sketcher/Gui/ViewProviderSketch.cpp

@@ -2586,6 +2586,11 @@ void ViewProviderSketch::drawEdit(const std::vector<Base::Vector2d> &EditCurve)
     editCoinManager->drawEdit(EditCurve);
 }
 
+void ViewProviderSketch::drawEdit(const std::list<std::vector<Base::Vector2d>> &list)
+{
+    editCoinManager->drawEdit(list);
+}
+
 void ViewProviderSketch::drawEditMarkers(const std::vector<Base::Vector2d> &EditMarkers, unsigned int augmentationlevel)
 {
     editCoinManager->drawEditMarkers(EditMarkers, augmentationlevel);