Create vtkBoundedWidgetRepresentation to handle Widget Outline cropping

Different implicit representations implement a "crop at outline" feature,
where the drawn widget is clipped by a bounding box composed
of the input data bounding box extended to contain widget Origin.

This factorizes this feature.
We use inheritance and intermediate class (vtkBoundedWidgetRepresentation),
to limit API evolution of concrete vtkImplicitXXXRepresentation.

Ported classes: vtkImplicitConeRepresentation,
vtkImplicitCylinderRepresentation, vtkImplicitAnnulusRepresentation
vtkImplicitPlaneRepresentation

Newly supported class: vtkImplicitFrustumRepresentation
(it was using a fixed size, instead of dynamic one)