Bug 18198: MARC21: Further improve handling of 5XX$u in GetMarcNotes

Bug 18198: MARC21: Further improve handling of 5XX$u in GetMarcNotes

Bug 14306 only handled field 555 in MARC21 as an URI. But a lot of other
5XX fields have a $u subfield for URIs; actually $u is not used in any
other way. This patch generalizes the change made for 555 and extends
it to all 5XX $u.

Test plan:
[1] Run t/Biblio.t
[2] Run t/db_dependent/Biblio.t
[3] Edit a MARC21 record. Add a URL into 505u, 520u, 555u.
[4] Check presentation on opac-detail (tab Title notes)
[5] Check presentation on catalogue/detail (tab Descriptions)

Signed-off-by: Marcel de Rooy <m.de.rooy@rijksmuseum.nl>
Signed-off-by: Katrin Fischer <katrin.fischer.83@web.de>
Signed-off-by: Josef Moravec <josef.moravec@gmail.com>
Signed-off-by: Jonathan Druart <jonathan.druart@bugs.koha-community.org>