This patch uses %index_field_convert to perform 'yr' limit.
Test plan:
1) Apply patch
2) Use Elasticsearch searchengine
3) Go to advanced search with 'More options'
4) Perform a search with a year limit (value or range)
5) Check results are correct
Signed-off-by: David Nind <david@davidnind.com> Signed-off-by: David Nind <david@davidnind.com> Signed-off-by: Kyle M Hall <kyle@bywatersolutions.com> Signed-off-by: Jonathan Druart <jonathan.druart@bugs.koha-community.org>