Sampling: uFoI vs. pFoI

[KathiSchleidt]

In the examples (e.g. GW_ExSitu_QualityObservation) we have a Sampling with 2 FoIs, would ideally be uFoI & pFoI:

• uFoI : 507AC00 (the hydrogeounit)
• pFoI : the spatial sample at the well

Can we add this differentiation between uFoI & pFoI to STA, SOSA?

[sgrellet]

complementary note, OMS does not make that difference (see diagram below) and just uses the relation role +featureOfInterest

We may need to generate a change request here