Bug 35721: ModItemTransfer -> Koha::Item->request_transfer - returns.pl

Bug 35721: ModItemTransfer -> Koha::Item->request_transfer - returns.pl

This patch replaces the call to ModItemTransfer in circ/returns.pl with
a call to Koha::Item->request_transfer and
Koha::Item::Transfer->transit.

Test plan
1) Set 'AutomaticItemReturn' to "Don't"
2) Check an item in at a location other than it's 'home' or 'holding'
   branch
3) Note you should be asked a about returning the item to another branch
4) Opting to not proceed should NOT result in a row in the
   branchtransfers table
5) Option to proceed (either with a print slip or just 'OK') should
   result in a branchtransfer from the current checkin branch to the
home or holding branch depending on the circulation rules.
5a) The item should be marked as immediately in transit in, i.e. the
   'datesent' set to today.

Signed-off-by: David Nind <david@davidnind.com>
Signed-off-by: Martin Renvoize <martin.renvoize@ptfs-europe.com>
Signed-off-by: Phil Ringnalda <phil@chetcolibrary.org>
Signed-off-by: Marcel de Rooy <m.de.rooy@rijksmuseum.nl>
Signed-off-by: Katrin Fischer <katrin.fischer@bsz-bw.de>