Replace existing finance API and domain model with model from RFC 18

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.

Files can be in this repo: https://github.com/Ed-Fi-Exchange-OSS/MetaEd-Contrib/tree/EdFiXFinance-v1_ME_v2

This ticket will:

1. Using MetaEd, update Finance domain with the new Finance model by:

     a. Removing files related to the old Finance domain

     b. Moving files from repo: https://github.com/Ed-Fi-Exchange-OSS/MetaEd-Contrib/tree/EdFiXFinance-v1_ME_v2

     c. Update/Improve element definitions

2. Review MetaEd  definitions

3. Add descriptor files to Ed-Fi Data Standard

4. Review descriptor values

From Ed-Fi-Model, files to be removed are:

DomainEntity/Account

DomainEntity/Actual

DomainEntity/Budget

DomainEntity/ContractedStaff

DomainEntity/Payroll

DomainEntity/AccountCode

Shared/AccountCodeCategory

Shared/AccountCodeNumber

descriptor/AccountClassification

From Ed-Fi-Standard, file to be removed:

Descriptors/AccountClassificationDescriptor

For Ed-Fi-Standard, files to be added are:

Descriptors/AccountTypeDescriptor (revenue, Expenditure, Balance Sheet)

Descriptors/FinancialCollectionDescriptor (0 to 30 days, 31 to 45 days, 46 to 60 days, 61 to 75 days,76 to 90 days)

Descriptors/ReportingTagDescriptor (Federal, State, Local)