[WFLY-245] Add support for cross-site replication of Infinispan caches via RELAY2
[WFLY-245] Rebase against master.  Bump schema/model versions to 2.0.x

Conflicts:
	clustering/infinispan/pom.xml
[WFLY-245] Basic x-site testcase implementation.
[WFLY-245] Add backup-for resource to shared state cache.