Create a piece of documentation relating the process-structure-property triangle to PMDco

[webhart]

The process-structure-property triangle is a common dogma of the MSE community. From the feedback, it seems that the differentiation between "structure" (which is quality in BFO terms) and the "property" (which is realizable entity in BFO terms) is not clear enough to our audience. As a consequence:

• Add a prominent pattern/section in the docs to make that clear
• Write corresponding comments in the respective class annotations.

In the same context the applicability of (intensive) SDCs to "portions" (vs. "objects") should be checked:

• Add a prominent pattern/section in the docs to make that clear
• Write corresponding comments in the respective class annotations.