New BC and DSS status attribute

The BC and SDTM Dataset Specializations (DSS) Data Models need to include a 'Status' attribute to indicate whether a BC or DSS is active vs. retired.

Rationale: BCs and DSS may need to be retired, e.g., when NCI retires a concept or when a decision has been made by the BC Curation team to change how the BC is constructed. Currently, there's no mechanism to retire BCs or DSS. Our work around is to update the short_name and definition with [RETIRED] to indicate that the BC or DSS should not be used.