Bug 21142: Open uploaded files in utf-8 - batch mod/del

Bug 21142: Open uploaded files in utf-8 - batch mod/del

Batch item/record modification/deletion tools does not open uploaded
files in utf-8

Test plan:
Edit and delete records and items using a file which will contain:
valid and invalid barcodes with and without utf-8 chars (💕)

You should see the warning message:
 "The *** 39999000💕001679 does not exist in the database."

Signed-off-by: Owen Leonard <oleonard@myacpl.org>
Signed-off-by: Tomas Cohen Arazi <tomascohen@theke.io>
Signed-off-by: Nick Clemens <nick@bywatersolutions.com>