Granular invalid data detection for Vandelay item import

Granular invalid data detection for Vandelay item import

When an import item contains any data for a field, the code now verifies
the data is valid for the selected field.  When the data is not valid,
we capture information on which field is invalid and what data was used
for the field (import_error, error_detail) so it can be reported in the
interface.

This adds new import_errors:

import.item.invalid.status
import.item.invalid.price
import.item.invalid.deposit_amount
import.item.invalid.owning_lib
import.item.invalid.circ_lib
import.item.invalid.copy_number
import.item.invalid.circ_as_type

Signed-off-by: Bill Erickson <berick@esilibrary.com>