NCIP server: use Koha::Hold and add lowestPriority to ILL requests
NCIP server: use Koha::Hold and add lowestPriority to ILL requests

also add some more error handling

digibib/koha-salt-docker,digibib/koha-docker,digibib/koha-docker,digibib/koha-docker,digibib/koha-salt-docker,digibib/koha-docker,digibib/koha-salt-docker,digibib/koha-docker,digibib/koha-docker,digibib/koha-salt-docker,digibib/koha-salt-docker