Allow InfinispanConnector(s) to create configurable Infinispan cachemanagers

Currently, the Infinispan connector has two behaviors

1. Use default cache manager.
2. Lookup cache manager via jndi.

while #2 is somewhat appealing, if looking to simply out of the box deploy ModeShape, it is not possible in this scenario. In addition, #1 limits the usability of ModeShape as default Infinispan doesn't do much. As a result, I would like to propose to create a third option, supply infinispan a configuration file/configuration xml that can be used to configure the cache manager.

The way I could see it work is:

ModeShape allows a child element w/ the infinispan configuration in the <mode:source> tag that is essentially the standard infinispan configuration.
ModeShape allows a new attribute mode:infinispanConfigFile that has the file that is used.

My concern w/ the second is that system administrators should be able to modify this file, without needing to repackage the JAR file that has this as contents. Development teams need not necessarily be able to define the storage of infinispan.