Allow passing additional parameters with query request.

A small addition to ElasticSearch allowing to pass additional, not parsed parameters along with the query, for example like the following:

```
{
 "from" : 0,
 "size" : 60,
 "query" : {
  "term" : { 
   "name" : "value" 
  }
 },
 "additional" : { 
  "token" : "nabsy26dsqnbu1276", 
  "userId" : "12345" 
 }
}
```