Dedicated Infinispan module for branch 4.5

Related to the following issue, this is the version of the patch for branch 4.5 :
https://hibernate.atlassian.net/browse/HSEARCH-1692

! Not much was cherry-picked !

Changes are the same conceptually as PR #675 but I had to rewrite most of it, for example
all configuration files are now edited to match Infinispan 6 which uses a different format.

Interestingly enough I couldn't get this branch to fail as when it falls back to use the "main" slot of using Infinispan from WildFly, that happens to be the same slot in this case.
Still we need the fix for others to be able to build this branch and drop it on a different version of the application server.
yea sorry that's a temporary placeholder.
Discussed the final name on JDG mailing list and with @emmanuelbernard  as you were not on IRC ;-)
Our conclusion is to call it "org.hibernate.search.infinispan-storage"