Bug 29355: Make pickup location dropdowns RESTdefaultPageSize agnostic

Bug 29355: Make pickup location dropdowns RESTdefaultPageSize agnostic

This patch makes the select2 dropdowns for pickup locations not be
limited to the RESTdefaultPageSize syspref limit.

To test:
1. Have less than 20 libraries in your system as valid pickup locations
2. Place a hold via the staff client
=> SUCCESS: See that all your libraries appear in the pickup location dropdowns at the bib and item level
3. Update RESTdefaultPageSize, set the value to something lower than your count of pickup libraries
4. place another hold
=> FAIL: Your pickup location list gets cut off and only shows as many locations as RESTdefaultPageSize allows
5. Apply this patch
6. Repeat 4
=> SUCCESS: All your pickup locations show
7. Sign off :-D

Signed-off-by: Tomas Cohen Arazi <tomascohen@theke.io>
Signed-off-by: David Nind <david@davidnind.com>
Signed-off-by: Martin Renvoize <martin.renvoize@ptfs-europe.com>
Signed-off-by: Jonathan Druart <jonathan.druart@bugs.koha-community.org>