Fix naming integration for better embeddability
Currently z2 registers InitialContextFactoryBuilder and ObjectFactoryBuilder implementations with the naming manager to have a completely pervasive naming provider programming model.
That however can happen exactly once and may prohibit embedding of Z2 into other environments.
On the other hand there is really only the "components" and the "resources" scheme that are actively used. And finally, the standard extensions measures of JNDI (via jndi.properties in the visibility of the current thread's context class loader) already provides for some extensibility.
So: Port the naming integration to standard means of extensibilty.