Add a Cassandra Mailbox implementation, contributed by Philippe Benoit (MAILBOX-12)

git-svn-id: https://svn.apache.org/repos/asf/james/mailbox/trunk@1617517 13f79535-47bb-0310-9956-ffa450edef68
Create .gitingore
Create module for elasticsearch
Create the first test
Create the first class to provide ES