EC2: Include a better distributable application as example deployment

Package eap7-jboss-ec2-eap-samples contains cluster-demo.war which is distributable, but does not offer a nice way to test session failover, since it holds no state. It only prints the time of request. Something like https://github.com/clusterbench/clusterbench might work better, though the approval of rhn-engineering-rhusar might be required.

Note that this has no impact on our testing. It's just for user's convenience.