Bug 19739: Add default ES configuration to koha-conf.xml

Bug 19739: Add default ES configuration to koha-conf.xml

Bug 18571 added default ES configuration for packaging config.

This patch adds it to dev install in koha-conf.xml.
Database name is used in index_name to allow multiple installs.

Test plan :
- Run dev install
- Install ElasticSearch server and Koha deps
- Enable ElasticSearch in Koha
- Check indexing and searching works directly

Signed-off-by: Brendan Gallagher <brendan@bywatersolutions.com>
Signed-off-by: Nick Clemens <nick@bywatersolutions.com>
Signed-off-by: Jonathan Druart <jonathan.druart@bugs.koha-community.org>
Signed-off-by: Nick Clemens <nick@bywatersolutions.com>