refactor: rename Vtk classes by removing the vtk prefix to follow project naming conventions

src/Vtk/vtkViewport.h

@@ -28,7 +28,8 @@ namespace uLib {
 namespace Vtk {
 
 struct ViewportData;
-class vtkHandlerWidget;
+class HandlerWidget;
+class ObjectsContext;
 
 /**
  * @class Viewport
@@ -85,7 +86,7 @@ protected:
     // Internal puppet registration
     void RegisterPuppet(Puppet* p, bool isPart = false);
     void UnregisterPuppet(Puppet* p);
-    void ObserveContext(class vtkObjectsContext* ctx);
+    void ObserveContext(ObjectsContext* ctx);
 
     struct ViewportData *pv;
     Axis                                         m_GridAxis;