[Tech memo] Subclass improvements for parsing modularity to support FRA

[andrew-jameson]

Description:
Spawning out of #3400, we will plan to write up a technical memo for proposed improvements to RowSchema and Field classes to be modular between the differing data types. As discussed during our prior office hours, subclassing RowSchema, Field, and others to be FRA-specific should be the primary changes proposed.

Acceptance Criteria:

• Technical memo documenting a proof of concept for FRA-specific rework of existing parsing classes
• Testing Checklist has been run and all tests pass
• README is updated, if necessary

Tasks:

• Investigate refactoring possibilities related to RowSchema and Field to work seamless with both data types (TANF/SSP or FRA)
• Run Testing Checklist and confirm all tests pass

Notes:

• This can be done in parallel with [Tech Memo] Refactoring backend parsing logic for FRA report integration #3416, but it is preferred for [Tech Memo] Refactoring backend parsing logic for FRA report integration #3416 to come first.

Supporting Documentation:

Open Questions: