Bug 26504: Remove the use of jquery.checkboxes plugin from checkout notes page

Bug 26504: Remove the use of jquery.checkboxes plugin from checkout notes page

This patch removes the inclusion of the jquery.checkboxes plugin from
the checkout notes page. It is unused.

To test, apply the patch and confirm that the AllowCheckoutNotes system
preference is enabled.

- Go to Circulation -> Checkout notes.
- Confirm that the "Select all" and "Clear all" links work correctly.

Signed-off-by: David Nind <david@davidnind.com>
Signed-off-by: Katrin Fischer <katrin.fischer.83@web.de>
Signed-off-by: Jonathan Druart <jonathan.druart@bugs.koha-community.org>