Bug 27733: Add "_sort_by" paramter to pickup_locations API query

Bug 27733: Add "_sort_by" paramter to pickup_locations API query

On the place hold page in the staff interface, add a "_sort_by"
parameter with the "name" value so that the list of libraries is
returned in name order.

To test, apply the patch and locate a title in the staff interface which
has holds on it.

- View the holds information for that title.
- In the table of exising holds, expand the "Pickup library" dropdown
  for any of the entries. The list of libraries should be in order by
  library name.

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