Add constructor arguments to ExtendedStatsAggregation.
Add constructor arguments to ExtendedStatsAggregation.

saimaz/ElasticsearchDSL,abhiesa-tolexo/ElasticsearchDSL,asev/ElasticsearchDSL,mansimas/ElasticsearchDSL,tadcka/ElasticsearchDSL,ongr-io/ElasticsearchDSL