Enforce LocalEducationAgencyId in Schools

Based on the SC deployment we have run into an issue that may require a slight change to Schools. Currently the only field in School that is non-nullable is SchoolID, but that doesn't allow for situations like in SC where districts may have a summer school school ID that may not be unique in the state but is unique when combined with the LEA ID.

The issue stems from the int length limit on the EdOrg and related ID fields. Our solution was to send the School + LEA ID pairs to schools table for district ODS, but in the state ODS this fails because only SchoolID is required. For an initial solution, expanding the required field and the keys on that table to include LEA ID.

Tagging ea-mtenhooremondal1026 for further background and visibility.