API: Return UUID when approving transfers
API: Return UUID when approving transfers

Return the transfer's UUID when getting unapproved transfers and when
approving transfers. This makes it easier to track after approval.

eckardm/archivematica,artefactual/archivematica,michal-ruzicka/archivematica,sevein/archivematica,michal-ruzicka/archivematica,artefactual/archivematica,michal-ruzicka/archivematica,eckardm/archivematica,eckardm/archivematica,eckardm/archivematica,sevein/archivematica,sevein/archivematica,michal-ruzicka/archivematica,sevein/archivematica,artefactual/archivematica,artefactual/archivematica