Bug 15319 - Use Bootstrap modal for MARC preview when performing batch record modific...

Bug 15319 - Use Bootstrap modal for MARC preview when performing batch record modifications

In order to reduce the number of dependencies for common interactions we
should attempt to use Bootstrap modals in place of Greybox ones.

This patch modifies the batch record modification page so that the
"Preview MARC" link triggers a preview in a Bootstrap modal.

To test:

1. Apply the patch and navigate to Tools -> Batch record modification.
2. Submit multiple biblionumbers for batch modification.
3. In the results list, click the "Preview MARC" link for multiple
   results and confirm that the correct data is shown each time.
4. Use the "Modify record using the following template" menu to change
   the modification template.
5. Confirm that the "Preview MARC" links still work and show data
   correctly modified by your newly chosen template.
6. Repeat steps 2-5 with authority record numbers.

Signed-off-by: Frédéric Demians <f.demians@tamil.fr>
  Works as described. No regression.

Signed-off-by: Jonathan Druart <jonathan.druart@bugs.koha-community.org>
Signed-off-by: Kyle M Hall <kyle@bywatersolutions.com>