Bug 26051: We should sort callnumber based on cn-sort

Bug 26051: We should sort callnumber based on cn-sort

In zebra we sort by callnumber using 8007 cn-sort

We should do the same in elasticsearch

To test:
1 - Have Koha using Elasticsearch
2 - Perform a search
3 - Attempt to sort by callnumber
4 - Error in logs: No mapping found for [local-classification__sort]
5 - Apply patch
6 - Restart all
7 - Perform a search and sort by callnumber
8 - Success!

Signed-off-by: Fridolin Somers <fridolin.somers@biblibre.com>
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>