Bug 7189 - preference to control if returning lost items gives refund

Bug 7189 - preference to control if returning lost items gives refund

Right now when you return an item that was lost the patron's card is
credited with the lost fee, but not all libraries refund lost fees
and sometimes the fee is refunded after the patron has paid for it,
causing all kinds of financial issues.

Adds the syspref RefundLostItemFeeOnReturn to control whether
returning a lost item refunds the fee charged for losing that
item. Enabled by default to maintain Koha's current functionality.

Signed-off-by: Owen Leonard <oleonard@myacpl.org>
Passed-QA-by: Paul Poulain <paul.poulain@biblibre.com>
Signed-off-by: Jared Camins-Esakov <jcamins@cpbibliography.com>