Add connector to latest Infinispan 5.x

The latest version of Infinispan is 5.1.1.Final, but our 2.7.0.Final connector uses Infinispan 4.2.1.Final. Because Infinispan's public API has changed, the 2.7.0.Final connector can't simply be forced to use 5.x. Instead, we either need to upgrade the current connector (which means nobody would be able to use 2.8 with Infinispan 4.x), or we need to create a new connector that uses Infinispan 5.x. I think the latter will make more sense for users, allowing them to choose.