SPMS12 — Enhance PatternSection body to allow for more than raw strings as content

Consumers of SPMS have requested the ability to include diagrams, pointers to existing documents, etc., in the section bodies.

Provide guidance on using PatternSection::body as a URI for external resource tracking.

A request was made to allow for richer descriptions in PatternSections than simple strings. The simplest, backward compatible patch for this is to provide guidance such that, if a user enters a simple URI into the body property, that URI is expected to point to an external resource that contains the description for that PatternSection.

Specifically, Word files were requested. As we have no functionality within the OMG specs for directly embedding this data within a model in a meaningful manner, the URI method is workable.