Changes

[Sofa.GUI.Common] Handle object selection in BaseViewer (#5636)

* Add a way to handle object selection in viewer.

It is usefull to be able to handle the currently selected object in the viewer to
implement visual feedbacks. This is done by adding a vector of selected node/object
as well as a drawSelection method to do the rendering.

* Replace std::vector with std::set

* FIXUP

* Add configuration parameters to control the selectionDrawing

* Update BaseViewer.cpp

Remove commented code.

* Update BaseViewer.cpp

Integrate comments

* Update Sofa/GUI/Common/src/sofa/gui/common/BaseViewer.cpp

Co-authored-by: Hugo <hugo.talbot@sofa-framework.org>

* Update Sofa/GUI/Common/src/sofa/gui/common/BaseViewer.cpp

---------

Co-authored-by: Hugo <hugo.talbot@sofa-framework.org>