Reorganise JCache info

https://openliberty.io/docs/latest/distributed-caching-jcache.html

This container topic is largely about configuration, which should instead be in the feature config reference topic: https://openliberty.io/docs/latest/reference/feature/sessionCache-1.0.html

It is not helpful for this to be the container topic. The Distributed caching topic should be the container topic: https://openliberty.io/docs/latest/distributed-session-caching.html It introduces the concept and gives context to anything else.

The topic about Infinispan starts with a generic shortdesc but it should mention Infinispan and why you might be using that as that's the point of the topic. Nothing in the whole intro section explains why you might choose Infinispan yet the topic assumes you're on OpenShift (which is not necessarily going to be the case). Is Infinispan the only option on OpenShift? Can it be used only on OpenShift? I'm not sure any of this context is given in the topic.

Start by comparing the distributed-caching-jcache.html, distributed-session-caching.html, and sessionCache-1.0.html topics to determine where the configuration content belongs. Then review configuring-infinispan-support.html, especially its introduction, for the missing Infinispan purpose and platform context. Done means the topics have the requested structure and the introductory context is clear.