Add IfcBorehole, IfcGeoScienceObservation and IfcGeoScienceFeature usages

[larswik]

There needs to be a possibility to:

1. Decompose an IfcGeoScienceObservation into IfcGeoScienceObservation parts
2. Assign an IfcGeoScienceObservation to an IfcBorehole
   Example:
   

• TEST A and TEST B are IfcGeoScienceObservation decomposed into several "smaller" IfcGeoScienceObservation at different depths.
• Both TEST A and TEST B are assigned to the IfcBorehole (where the observations were made)

4. Assign an IfcGeoScienceFeature to an IfcBorehole
   "In between" factual data, measured in a borehole (Book A - a) in the figure below) and interpreted data (Book B - c) in the figure below), interpretations may be made per borehole as an intermediate step before surfaic or volumetric features in the terrain are interpreted (b) in the figure below). The proposal is to create IfcGeoScienceFeature objects per borehole (assigned to the borehole) to represent this intermediate step.
   Example: