Bug 23830: Make Koha::AuthorisedValues use Koha::Objects::Limit::Library

Bug 23830: Make Koha::AuthorisedValues use Koha::Objects::Limit::Library

This patch makes Koha::AuthorisedValues inherit the
'search_with_library_limits' method from Koha::Objects::Limit::Library.
This was left out of the original implementation and this patch makes
this library have a similar implementation to that of Koha::ItemTypes,
etc.

To test:
1. Run:
   $ kshell
  k$ prove t/db_dependent/AuthorisedValues.t
=> SUCCESS: Tests pass!
2. Apply this patch
3. Notice Koha::AuthorisedValues now inherits this new library
4. Notice the overloaded ->search method is removed
5. Repeat (1)
=> SUCCESS: The behavior of the newly used method on the tests is the
same as before. We only changed the method name and how we pass the
library_id.
6. Sign off :-D

Signed-off-by: Martin Renvoize <martin.renvoize@ptfs-europe.com>
Signed-off-by: Jonathan Druart <jonathan.druart@bugs.koha-community.org>