Change schoolId from int32 to varchar 30 or int64

There exists a problem for South Carolina in which the Ed-Fi ODS cannot accept identifiers assigned to a school that are over specific character lengths since schoolId is set to int32. The proposal is to change the type to varchar 30, or, if int is required, int64. Further justification: identifiers for schools are essentially names; they are not aggregated but grouped by their values and potentially consolidated or compared. The underlying attribute values for schools may be added or subtracted but not school identifiers.