CRMsci Introduction update (scope, diagrams, supporting text)

The CRM SIG approved CRMsci V3.2. That version incorporates all the changes that stemmed from the harmonization of CRMsci with CIDOC CRM and CRMinf (the model for Observations, including Position Determination and its relation to the models for E13 Attribute Assignment and I1 Argumentation). This was a major update and the resulting version has been well thought through. However, the SIG anticipated that the introduction (text and diagrams) in CRMsci V3.2 would need to be updated to illustrate the model changes. 

This issue is an effort to redraft the relevant parts of the introduction plus the diagrams. 

N.b. The HW will appear shortly under here.