Add the ability to store a Staff email address for each associated Education Organization

Summary of outcomes for Data Standard 2.1

• Problem Addressed: Staff may be associated with multiple EducationOrganizations and have a different "work" email address for each EducationOrganization. The current model only allows for one work email address to be stored and does not provide a way to specify with which EducationOrganization the email address is associated. In addition, it has also been seen in field work that there are different needs behind "external" (directory-style) contacts, and more "internal" use case (student and staff records). In the former case, you will often have a contact for a role like "CRDC Coordinator" or "Help Desk Contact" - this model change addresses those needs.
• High-level Reasoning: By creating a new association, StaffEducationOrganizationContactAssociation, an email address (and other contact details) may be provided for each EducationOrganization with which a staff member is associated. 
• Changes Made: Created StaffEducationOrganizationContactAssociation between Staff and EducationOrganization with shared string ContactTitle as part of identity; Included required shared string ElectronicMailAddress, optional common type Address, optional reference to ContactTypeDescriptor, and a reference to the common type Telephone as an optional collection

Original ticket description follows:

Currently email addresses are managed using the StaffElectronicMail entity. In the ODS, the primary key on this table allows at most one of each type of email address to be stored. However, this doesn't model the domain well when staff span multiple organizations, as it would result in "thrashing" of the data. It also limits options around managing user logins where an SSO system has not been implemented.

Recommendation is to add an ElectronicMailAddress attribute to the StaffEducationOrganizationEmploymentAssociation to generally allow the capture of an email address for a Staff member associated with their education organization (i.e. district) of employment.