Address inconsistency in Session.Term

Summary of outcomes for Data Standard 2.1

• Problem Addressed: Model annotation does not provide enough clarity for the difference between a Session and a Session.Term.
• High-level Reasoning: Through research and discussion, it has been suggested that the existence of both the Session and Term concepts is redundant and that many are in favor of a flatter structure. Ideally, the two concepts could be merged with Session being renamed "Term"
• Changes Made: Updated annotation for the Session domain entity to read: "A term in the school year, generally a unit of time into which courses are scheduled, instruction occurs and by which credits are awarded. Sessions may be interrupted by vacations or other events."; Updated annotation for Session.Term to read: "An enumeration value indicating the term (e.g. "Fall Semester", "Second Quarter", "Summer Semester", etc.)."

Original ticket description follows:

I noted that there is a strange inconsistency between the Ed-Fi default descriptors for terms (TermDescriptor), and the term types (TermMapType). This relates to other data standard items and the proposal to put SessionName into the Session key, and drop Term (see linked ticket).

The inconsistency Is:

• The default descriptors represent specific instances within a year (e.g. "Fall Semester", "First Trimester" etc.)
• The type enumerations those are mapped to represent a category (e.g. "Trimester", "Semester" etc.)

The definitions also differ:

• Descriptor type: "This descriptor defines the term of a session during the school year (e.g., Fall Semester)."
• Term type: "The type of the session during the school year (e.g., Fall Semester)."

It is odd to map an instance to a category. In some cases that might work, but in many cases relying on the back end type simply results in a loss of – likely important – data. The type mapping is optional, so it may not cause problems, but it's utility seems questionable.