Orders, alternative implementation: fetch and cache vendors only when needed

[branchedelac]

An alternative to #516

Fetching all organizations may be unnecessarily time-consuming for libraries with many organizations (eg #631), but where not all organizations are associated with orders.

Perhaps it would be preferable to instead fetch organizations only if they are encountered in the legacy data, with a CQL query to search by code. In most cases this will mean more API calls to FOLIO, but they will be distributed across the process so should not cause too much load. Any organization that has already been fetched can also be cached and reused in case it is referenced in ore orders.

Compare with how users are fetched and cached in the feefine mapper:
https://github.com/FOLIO-FSE/folio_migration_tools/blob/ef76b4bdbd3814adb755cfafef0e8ca87fc3af36/src/folio_migration_tools/mapping_file_transformation/manual_fee_fines_mapper.py#LL236C9-L236C28