Create UML and associated diagrams for updated Finance domain

A community Finance Working Group defined a new Finance model that would replace the existing one.  It was documented in an RFC at https://techdocs.ed-fi.org/display/GOV/ED-FI+RFC+18+-+FINANCE+API.

To ensure that the new model covers all the aspects of the older model, DATASTD-1657 analyzed the older model to make sure that that the new model covered all aspects.  This analysis resulted in the recommendation to add the following new entities to the new model as part the process of moving it into core:

LocalPayroll

• Staff reference
• LocalAccount reference
• Amount
• AsOfDate
• FinancialCollection [0..1]

LocalContractedStaff

• Staff reference
• LocalAccount reference
• Amount
• AsOfDate
• FinancialCollection [0..1]

LocalEncumbrance

• LocalAccount reference
• Amount
• AsOfDate
• FinancialCollection [0..1]

This is additive to the new financial model and is nonbreaking to the early implementations. 

This ticket will:

1. Create/update the UML for the new Finance domain