Implement legacy OLD tables in DativeBase

[jrwdunham]

Problem: DativeBase should have its own DB schema. However, initially we want DativeBase to be able to read legacy OLD data. Once we are ready to move all OLDs over to DativeBase, we can abandon the legacy schema.

A/C:

• Implement the OLD MySQL schema—currently encoded in SQLAlchemy ORM DSL in Python—as a MySQL schema in DativeBase.
  • We want DativeBase to be able to read the legacy OLD MySQL tables.
• Ensure that DativeBase can perform all of the core reads on an arbitrary, existing legacy OLD MySQL database table-set that the current OLD can.