Bug 7041: Sort >1000 search results with sortmax parameter in zebra config file

Bug 7041: Sort >1000 search results with sortmax parameter in zebra config file

By default, zebra does not sort more than 1000 records (search results). You
can increase this number by adding the sortmax parameter in zebra-biblios.cfg.

Putting this value in Koha's zebra config file will make this default value
visible and make it easier to increase it if one prefers that.

Signed-off-by: Chris Cormack <chrisc@catalyst.net.nz>
Signed-off-by: Paul Poulain <paul.poulain@biblibre.com>