Implementing second level classLoading and JSonProvider

[clebertsuconic]

I am having issue with Artemis in the following case.

• a RMI Call is made through our management, and we have no control over the TCCL. We would need to make such controls on our app, and I believe it would be better to be part of the provider, hence this PR.
• The provider is making excessive classloading operation for any JSON created. it would be better to cache results. Instead of caching it forever I used a SoftReference here.

for more information, this was discussed on a pull request on Artemis at : https://github.com/apache/activemq-artemis/pull/684