Bug 25570: Paginate results by default in objects->search

Bug 25570: Paginate results by default in objects->search

This patch makes the helper paginate the resultsif no pagination
parameters are passed.

Page number defaults to 1, and the page size to the RESTdefaultPageSize
syspref value.

To test:
1. Apply the regression tests patch
2. Run:
   $ kshell
  k$ prove t/db_dependent/Koha/REST/Plugin/Objects.t
=> FAIL: Pagination is not enforced by default
3. Apply this patch
4. Repeat 2
=> SUCCESS: Results are paginated
5. Sign off :-D

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