Bug 14025: Fix 865u-links in the OPAC for NORMARC

Bug 14025: Fix 865u-links in the OPAC for NORMARC

The display of links found in 856$u for NORMARC has not been keeping up with
the one for MARC21, and several sysprefs have not been implemented. This
patch tries to fix that.

Affected sysprefs:
- OPACURLOpenInNewWindow
- URLLinkText
- OPACDisplay856uAsImage
- OPACTrackClicks

To test:
- Make sure you have a record with a URL in 856$u and marcflavor = NORMARC.
  (It does not have to be a full NORMARC setup or a NORMARC record, just make
  sure you are viewing the record through the NORMARC XSLT files.)
- View the record both in a result list and in detail view
- Check that the 4 involved sysprefs affect the display in the expected ways

Signed-off-by: Bernardo Gonzalez Kriegel <bgkriegel@gmail.com>
Tested on NORMARC setup and XSLTs
Works as described, each syspref works
No koha-qa errors

Signed-off-by: Jonathan Druart <jonathan.druart@koha-community.org>
Since it only affects NORMAC, I trust in Magnus :)
Signed-off-by: Tomas Cohen Arazi <tomascohen@gmail.com>