Migrate deprecated warehouse connection operations
warehouseAddExternalRelation, warehouseUpdateExternalRelation, and warehouseRemoveExternalRelation are deprecated. Migrate to buildingIntegrationConnectionsCreate, buildingIntegrationConnectionsUpdate, and buildingIntegrationConnectionsRemove. The old operations still work.
The warehouseExternal query and Warehouse.externalData are also deprecated. Read buildingIntegrationConnections on Warehouse or Integration instead. Create takes buildingId and integrationId; update and remove take connectionId. A building can have only one active connection to an integration.