Add support for setBeansXml() on WebContainers, ResourceAdapterContainer...

...s and JavaArchives

@ALRubinger: I created this following our discussion yesterday.
I don't know if I got your idea right. If not maybe you could give me hint how it could be done better.

What I am unsure of is that
1. ContainerBase already implements the setBeansXML methods, also for EnterpriseContainers. Nevertheless they are not offered by the EnterpriseArchive interface.
2. WebContainerBase overloads the implementation of ContainerBase instead of having the implementations side-by-side in the hierarchy. (Unsure what approach is better.)