Collection of narrative content items in API

During the rule development related to narrative content the following inconsistency was noted:

The USDM dat amodel has two major branches
- 1 for the study version and corresponding designs
- 1 for the documentation and narrative content.
This allows us to separate the documentation from the actual digitized design. Cross references between the two parts occur.

In the USDM UML the narrative content items are an independent collection of items which can be reused across documents. In the API all independent collections are nested within the study version. This includes the narrative content items.
However, this implies that the narrative content items are now not stored in the study definition document part of the model.
Theerfore, for logical reasons, I like to propose to move the nesting 1 level higher to the study class.