Bug 12363: Add a switch to mark|do not mark items as returned when lost

Bug 12363: Add a switch to mark|do not mark items as returned when lost

There are several ways to mark an item an lost:
- item list view (catalogue/moredetail.pl, "Items" tab)
- cataloguing (cataloguing/additem.pl)
- Batch item modification tools (tools/batchMod.pl)
- The long overdue cronjob (misc/cronjobs/longoverdue.pl)

So far only the cronjob is configurable, the others mark the item as
returned (does the checkin).

This behaviour should be controlable using a syspref, to let libraries
choose what fit best for them.

Test plan:
Use the 2 options of the pref, mark checked out items as lost using the
different possibilities, and confirm that the behaviours make sense to
you

Signed-off-by: Séverine QUEUNE <severine.queune@bulac.fr>
Signed-off-by: Séverine QUEUNE <severine.queune@bulac.fr>
Signed-off-by: Kyle M Hall <kyle@bywatersolutions.com>
Signed-off-by: Jonathan Druart <jonathan.druart@bugs.koha-community.org>