Generate surface information for (GPU-friendly) bounded surface model

1. Agree the data model for surface-based solid modelling,.
2. Decide whether to work 'in Orange'
3. Create example conversions using data model (for use as references);
4. Implement the generation of surfaces from a selected set of VecGeom/Geant4 solids. 

This is the 3-month goal for the GPU-friendly solid modeling system.