Bug 26551: Correct modal markup to prevent long heading from overflowing

Bug 26551: Correct modal markup to prevent long heading from overflowing

This patch modifies the markup of the MARC framework import and export
modals so that CSS intended only for Bootstrap buttons isn't applied to
content in the modal.

The modal dialog markup was nested inside a ".btn-group" <div>, which
carries with it CSS that prevents text wrapping. Moving the modal markup
out of the button group while keeping it inside the <td> corrects the
problem. Lines have only been shifted and reindented.

To test, apply the patch and go to Administration -> MARC bibliographic
framework.

- In the table of frameworks, from the "Actions" menu, test both
  the "Import" and "Export" links. Both should work as expected.
- Confirm that the text of the heading on the "Import" modal wraps
  correctly.
- Test the same operations for a framework other than the default one.

Signed-off-by: David Nind <david@davidnind.com>
Signed-off-by: Martin Renvoize <martin.renvoize@ptfs-europe.com>
Signed-off-by: Jonathan Druart <jonathan.druart@bugs.koha-community.org>