Feature request - provide refresh and wait for active shards as configurables

[danizen]

This is a simple one to implement, but low priority. Some customers may want to manipulate the refresh and wait_for_active_shards parameters when committing data to ealsticsearch.

That would mean providing something else than Collections.emptyMap() here:

committer-elasticsearch/norconex-committer-elasticsearch/src/main/java/com/norconex/committer/elasticsearch/ElasticsearchCommitter.java

Line 591 in 2428e75

"POST", "/_bulk", Collections.emptyMap(), requestEntity);

This is related to my elasticsearch commit hang that caused my stop/resume strategy to fail, but isn't the cause of it. Just wanted to write down the need to configure these for some customers.