Bug 11360 - Disable barcode field and submit button when a hold is found

Bug 11360 - Disable barcode field and submit button when a hold is found

At the moment when scanning in returns, it can be easy to miss a hold
trap due to the fact that the barcode and submit are still active and
the barcode field is focused on. A librarian who is focused on scanning
can easily scan another item and pass over the form, which is equivalent
to clicking the "ignore" button.

Test Plan:
1) Apply this patch
2) Trap a hold, note the new modal
3) Check the hold in a second time
4) Note the new modal
5) For each modal, test each button

Signed-off-by: Christopher Brannon <cbrannon@cdalibrary.org>
Signed-off-by: Jonathan Druart <jonathan.druart@bugs.koha-community.org>