Bug 17530: Add Koha::IssuingRules->guess_article_requestable_itemtypes

Bug 17530: Add Koha::IssuingRules->guess_article_requestable_itemtypes

This routine looks at the issuingrules and makes a fast 'intelligent
guess' if article requests may be allowed for item types while
branch code and patron category may not be available.

We also add Koha::Biblio->may_article_request using the routine based
on default item type or parameter. Implemented as both class and instance
method. Added a few tests.

Test plan:
[1] Run t/db_dependent/Koha/IssuingRules/guess_article_requestable_itemtypes.t
[2] Run t/db_dependent/ArticleRequests.t to test Koha::Biblio changes.

Signed-off-by: Marcel de Rooy <m.de.rooy@rijksmuseum.nl>
Signed-off-by: Brendan Gallagher <brendan@bywatersolutions.com>
Signed-off-by: Chris Cormack <chrisc@catalyst.net.nz>
Signed-off-by: Nick Clemens <nick@bywatersolutions.com>