MODE-2188 Added management of index providers to Wildfly subsystem

It is now possible to specify the index providers and index definitions in the repository JSON configuration. They both can also be managed (sort-of) using the Wildfly configuration and CLI tools.

Additionally, ModeShape is no longer dependent upon Lucene or Hibernate Search; these can be re-added when we add a separate module for the not-yet-written Lucene 4.0-based index provider.