Consider making StudentProgramAssociation Eligibility and Services as new Associations

Creating a new StudentProgramEligibilityAssociation would:

• Allow the community to clearly define dates around eligibility versus active participation in a program
• Aid use cases where one system may need access to define eligibility but not participation (like the School Food Service Program)
• Remove BeginDate from the key of StudentProgramAssociation.

Moving the StudentProgramAssociation Services common type elements to a new association would address the growing complexity of data being stored in this common type.

These changes would be breaking to the model and should be reviewed for the next major release.