Feature request: ShapeRepresentatation Facet

It would be helpful to be able to specify that a product must use a specific Entity as its shape representation.

Example 1:

### Applicability

All elements with class IFCREINFORCINGBAR (required)

### Requirements

ShapeRepresentation must be class IFCSWEPTDISKSOLID

Example 2:

### Applicability

All elements with class IFCALIGNMENT

### Requirements

Shape Representation must be class IFCCOMPOSITECURVE or IFCGRADIENTCURVE

Perhaps this could be considered for the v1.1 roadmap?