WFLY-3175 & WFLY-3180 fixes

https://issues.jboss.org/browse/WFLY-3175
https://issues.jboss.org/browse/WFLY-3180

* Improves web sessions and stateful ejb eviction logic.
* Creates non-clustered version of org.wildfly.clustering.api services.  This has the following side-effects:
  + Web/ejb clustering code no longer needs OPTIONAL dependencies
  + Applications that use the public clustering API will function correctly when server uses non-HA profile