api/private/deposit_list: Add new endpoint to be used with datatables

Add new private API endpoint /1/private/deposits/datatables/ to list and
filter deposits whose responses are intended to be consumed by datatables
javascript framework used in deposits admin Web UI.

Originally that view was implemented in swh-web but for performance reasons
it has been decided to move it in swh-deposit, swh-web will then simply
forward the HTTP request to swh-deposit.

Related to T3128