Bug 26487: Add all MARC flavours for not-onloan-count search field

Bug 26487: Add all MARC flavours for not-onloan-count search field

In admin/searchengine/elasticsearch/mappings.yaml the search field not-onloan-count is defined for MARC21 on 999x.
This should be for all the MARC flavours, like in Zebra config.

Test plan:
1) On a UNIMARC database
2) Reset Elasticsearch mappings
3) Check search engine config to see field 'not-onloan-count' on 999$x
4) Same on a NORMARC database

Signed-off-by: Chris Cormack <chrisc@catalyst.net.nz>
Signed-off-by: Katrin Fischer <katrin.fischer.83@web.de>
Signed-off-by: Jonathan Druart <jonathan.druart@bugs.koha-community.org>