Bug 33778: Further polishing

Bug 33778: Further polishing

Use mock_preference.
Move final tests for BaseURLs into one subtest.
Change reset_config to allow passing parameters replacing some variables.
Copyright line.

Test plan:
Run t/Auth_with_shibboleth.t

Signed-off-by: Marcel de Rooy <m.de.rooy@rijksmuseum.nl>
Signed-off-by: David Nind <david@davidnind.com>
Signed-off-by: Martin Renvoize <martin.renvoize@ptfs-europe.com>
Signed-off-by: Tomas Cohen Arazi <tomascohen@theke.io>
(cherry picked from commit f951b553d413f4363184435db36b890950d2554b)
Signed-off-by: Martin Renvoize <martin.renvoize@ptfs-europe.com>