Bug 29471: Add display of MARC 520 to staff interface detail page

Bug 29471: Add display of MARC 520 to staff interface detail page

At the moment 520 only displays in the OPAC. With this patch it
also displays in the staff interface detail page.

To test:
* Find a record with 520 or add some 520 entries to a record
  Note: different ind. 1 values will result in different labels
* View the record in the staff interface and the OPAC
* Verify only the OPAC shows the 520 entries
* Apply patch
* Verify now the staff interface displays them as well

Signed-off-by: Phil Ringnalda <phil@chetcolibrary.org>
Signed-off-by: Katrin Fischer <katrin.fischer@bsz-bw.de>
Updated patch for displaying $u as link.

Signed-off-by: Marcel de Rooy <m.de.rooy@rijksmuseum.nl>
Restored signoff line from Phil. Change only for $u.
Signed-off-by: Tomas Cohen Arazi <tomascohen@theke.io>
(cherry picked from commit 256518bf75f4df70a62bfe401bd911473e629efd)
Signed-off-by: Martin Renvoize <martin.renvoize@ptfs-europe.com>