Bug 18318: Unicode support for Elasticsearch

Bug 18318: Unicode support for Elasticsearch

You must install the icu plugin for elasticsearch
https://www.elastic.co/guide/en/elasticsearch/plugins/current/analysis-icu.html

Once installed, apply this patch
Reindex your data, deleting the existing indexes
perl /home/vagrant/kohaclone/misc/search_tools/rebuild_elastic_search.pl
-d
Find (or add) some titles with accented characters
Verify that a search for the exact character or the unaccented version
works

Signed-off-by: Tomas Cohen Arazi <tomascohen@theke.io>
Signed-off-by: Julian Maurice <julian.maurice@biblibre.com>
Signed-off-by: Jonathan Druart <jonathan.druart@bugs.koha-community.org>
(cherry picked from commit 1404654d65baccacb2928f59171ec6f41d9b653b)
Signed-off-by: Fridolin Somers <fridolin.somers@biblibre.com>