Rename the accession field referencing the accession holder

When sending a basket from data-discovery to rare-basket, we include a field for each accession currently named contactEmail. As we now decided to not rely on the email, but directly on the accession holder, we need to refactor the codebase to:

• send the accession holder in rare-basket instead of the email https://forgemia.inra.fr/urgi-is/data-discovery/-/merge_requests/290
• find the accession holder based on this field in data-discovery