Bug 17374: Make use of fields from syspref 'DefaultPatronSearchFields' in patron...

Bug 17374: Make use of fields from syspref 'DefaultPatronSearchFields' in patron search fields dropdown

This patch preserves the current dropdown choices for patron search and adds fields from
the DefaultPatronSearchFields system preference

To test:
1 - View the regular patron search and note fields in dropdown
2 - Apply patch, ensure dropdown has not changed
3 - Add fields to DefaultPatronSearchFields, note they are available in
dropdown
4 - Ensure existing and new fields search properly

Signed-off-by: Kelly <kelly@bywatersolutions.com>
Signed-off-by: Maxime Dufresne <maxime.dufresne@inlibro.com>
Signed-off-by: Jonathan Druart <jonathan.druart@bugs.koha-community.org>
Signed-off-by: Martin Renvoize <martin.renvoize@ptfs-europe.com>