Bug 18200: Fix a potential issue with preceding space in GetMarcUrls

Bug 18200: Fix a potential issue with preceding space in GetMarcUrls

Trims the URL in order prevent prefixing a space with http://
Normally you won't have a preceding space here, but I saw it happening
one day and it does not cost much to resolve it.

Bonus: Adding few simple tests in t/db_dependent/Biblio.t.

Test plan:
[1] Run t/db_dependent/Biblio.t
[2] Add a 856$u with preceding space (MARC21)
[3] Check opac-detail, Online access with OPACXSLTDetailsDisplay empty.

Signed-off-by: Marcel de Rooy <m.de.rooy@rijksmuseum.nl>
Followed test plan, works as expected
Signed-off-by: Marc Véron <veron@veron.ch>
Signed-off-by: Jonathan Druart <jonathan.druart@bugs.koha-community.org>
Signed-off-by: Kyle M Hall <kyle@bywatersolutions.com>