Expose multiple Infinispan CacheManager instances in the same AS

An Infinispan CacheManager only has a single JGroups channel. If users wish to use different channels for different caches, the AS needs to provide a way to support that. The default AS config will only have a single CacheManager though.

Reasons for using different channels are for higher perf (less contention for shared locks) and to avoid unrelated messages queuing up in NAKACK/UNICAST because they come from the same sender. Note that JGRP-822 may eliminate the importance of the latter. If work on JGRP-822 proceeds rapidly to the point that the AS can consume it in 6.0.0, this JIRA may get deferred.