Bug 26960: Move batch item modification template JavaScript to the footer

Bug 26960: Move batch item modification template JavaScript to the footer

This patch modifies the batch item modification template so that the
JavaScript is in the footer, conforming with best practices.

The items form can contain <script> tags injected by cataloging plugins.
These are moved from the body of the page into the footer be repeating
the template loop that previously output the script tag.

To test, apply the patch and test the process of submitting items for
batch modification.

After submitting a batch of items, test the "Edit items" form.
Confirm that JavaScript-dependent interactions work correctly:

 - Select2-styled dropdowns
 - RegEx checkboxes
 - Datepicker
 - Plugins like:
   - dateaccessioned.pl on 952d
   - stocknumberam123.pl on 952i
   - callnumber.pl on 952o

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