The modeshape-jca module is incorrectly packaged

The current modeshape-jca module has the packaging type jar and uses the maven-rar-plugin to produce a JCA RAR artifact. However, because of the packaging type, this artifact is installed (and published in Nexus) as a jar instead of a rar.

Therefore, we should:

1. Create a new module modeshape-jca-rar which produces and packages a rar artifact - the main JCA adapter.
2. Change the current modeshape-jca module to only produce the modeshape-jca jar artifact. This second step means that the jar will be installed as well as a separate artifact.