Bug 15774: Fix additional fields filters

Bug 15774: Fix additional fields filters

Addresses the following QA comments:

1/ Regression:
On serials/serials-search.pl, the filters are not filled with what the
users searched for and the additional fields linked to an AV are not
displayed as a dropdown list.

4/ When searching an order, there is no way not to set a "all" value for
additional fields linked to AV.

5/ When searching an order and the search does not return any results,
the field should contain what the user filled in.

https://bugs.koha-community.org/bugzilla3/show_bug.cgi?id=15774#c10
Signed-off-by: Séverine QUEUNE <severine.queune@bulac.fr>
Signed-off-by: Jonathan Druart <jonathan.druart@bugs.koha-community.org>
Signed-off-by: Josef Moravec <josef.moravec@gmail.com>
Signed-off-by: Nick Clemens <nick@bywatersolutions.com>