FIBOFND12 — Move StructuredCollection from IND to FND

The concept of a structured collection is not limited to indicators, and should be moved from IND to FND/Arrangements. This is needed so that a new concept, that of a Record, can be added to FND/Documents (using the definition from the OMG's RMS), as a child of Document and of StructuredCollection, which is required to fix the definition of an account in FBC.

This is a first step in the process – a subsequent revision to IND should deprecate the current StructuredCollection concept in favor of this one added to FND.

Move StructuredCollection from IND to FND

The concepts of a structured collection and record are needed to support a number of downstream definitions, and because they are very general notions, they should be added to Foundations.