Bug 19209: Add ->is_paged method to Koha::Objects

Bug 19209: Add ->is_paged method to Koha::Objects

This patch adds ->is_paged to Koha::Objects. It is inherited from the underlying resultset
from DBIC so there's no code besides adding it to the known methods in AUTOLOAD.

Tests are added for the newly exported method.

To test:
- Apply this patch
- Run:
  $ sudo koha-shell kohadev
 k$ cd kohaclone
 k$ prove t/db_dependent/Koha/Objects.t
=> SUCCESS: Tests pass!
- Sign off :-D

Sponsored-by: Camden County
Signed-off-by: Kyle M Hall <kyle@bywatersolutions.com>
Signed-off-by: Marcel de Rooy <m.de.rooy@rijksmuseum.nl>
Signed-off-by: Jonathan Druart <jonathan.druart@bugs.koha-community.org>