Simplify and update combining filters
Simplify and update combining filters

Combining filters is only necessary for the or/should case.
The 'and' case is the default:
https://www.elastic.co/guide/en/elasticsearch/guide/current/combining-filters.html#bool-filter

:or and :and are deprecated and replaced by a 'bool' query
- https://www.elastic.co/guide/en/elasticsearch/reference/5.5/query-dsl-and-query.html

Comment is removed because it does not add anything anymore

alphagov/rummager,alphagov/rummager