title: Custom rescorer on NativeSearchQuery
body: <p>I installed a custom rescorer plugin on Elasticsearch but I couldn't find a way to call it by using ElasticsearchOperations.
  I'm using the NativeSearchQuery built by a NativeSearchQueryBuilder but I could only find a method to add a QueryRescore and not a custom one.
  Is there a way to use a custom rescorer plugin?</p>