ISPN-3350 The server RHQ plugin should allow adding/removing caches, stores and endpoints

* Added support for all arguments for Caches and Endpoints via RHQ
* Endpoint addition through RHQ is done by connector type
* Stores and Loaders now display in RHQ
* Stores/Loaders can now have more than 1 of a single type
* Added remove operations to all Caches/Stores/Loaders/Endpoints
* Refactored Loader and Store hierarchy to remove duplicate code

Still TODO
* Remote store needs work for remote-servers still
* JDBC Stores are not supported due to pending changes
* Security domain value for REST endpoint can probably be a resource ref in rhq-plugin to limit choices