Expanding the functionality of the ES client a bit

Change-Id: I1a3c9d0071fe80082f0f67318758c6bf0c3960e3
Making the index in constructor optional

Change-Id: I00b50867218a71961754356ad0d91e0426ea3e26
Merge "Expanding the functionality of the ES client a bit"
Merge "Making the index in constructor optional"