Add support for reading the staff data file into the database

[agideon]

This will require some additional tables and a new reader, but the reader can be based upon the already-existing convertStaffFileFromSkyward.pl which reads processes the staff data file. All that's required is adding the schema and the population of the schema.

This may introduce changes to how the existing student loader works as it may modify the student schema. For example, the homeroom table currently stores the name of a teacher merely as a string. This should likely be a foreign key into a staff table instead.

In fact, one way to start the loading of staff might be to make that change to the student loader, which will at least partially populate the staff table(s).