Provide API to enlist the resource with TransactionManager

Currently, Infinispan will automatically enlist the transaction when a transaction is bound to the executing thread. However, in cases like Teiid where remote access to Infinispan access is wrapped with a resource-adapter (RAR) the resource adapter does the explicit enlisting or delisting. For this there needs to be API provided by Infinispan Cache like

RemoteCacheManager.getXaResource()

where it can access the XA resource.