Reduce code duplication to support different ES versions

[jerome73]

Expected behavior and actual behavior.

We have as many implementations of ES client service as there are versions of ES supported by logisland while the code is almost the same between versions i-e:
Elasticsearch_2_3_3_ClientService.java
Elasticsearch_2_4_0_ClientService.java
Elasticsearch_5_4_0_ClientService.java

The idea would be to avoid this code duplication that involves to support as many codes as there are versions of ES.

Steps to reproduce the problem.

Specifications like the version of the project, operating system, or hardware.