Bug 21206: Replace C4::Items::GetItem

Bug 21206: Replace C4::Items::GetItem

Note: This is here for information purpose, feel free to test it if you
wan to play with it.

TODO: C4::Reserves::_get_itype is not longer in use

No more GetItem must be returned by:
git grep GetItem|grep -v GetItemsAvailableToFillHoldRequestsForBib|grep
-v GetItemsForInventory|grep -v GetItemsInfo|grep -v
GetItemsLocationInfo|grep -v GetItemsInCollection|grep -v
GetItemCourseReservesInfo|grep -v GetItemnumbersFromOrder|grep -v
GetItemSearchField|grep -v GetItemTypesCategorized|grep -v
GetItemNumbersFromImportBatch|cut -d':' -f1|sort|uniq

Signed-off-by: Josef Moravec <josef.moravec@gmail.com>
Signed-off-by: Tomas Cohen Arazi <tomascohen@theke.io>
Signed-off-by: Tomas Cohen Arazi <tomascohen@theke.io>
Signed-off-by: Nick Clemens <nick@bywatersolutions.com>