Add superinterface(s) for common property methods

The ClientRequestContext, ContainerRequestContext, InterceptorContext, and Configuration interfaces each have getProperty(String) and getPropertyNames() methods and each except Configuration have setProperty(String, Object) and removeProperty(String) methods but they do not each extend any common super-interface(s). As such, code dealing with properties across these interfaces has to be duplicated, work with adapter objects, etc. 

Some common super-interface(s) would be very beneficial. e.g. A Properties interface could contain getProperty(String) and getPropertyNames() and a MutableProperties interface could extend Properties and add setProperty(String, Object) and removeProperty(String)'; ClientRequestContext, ContainerRequestContext, and InterceptorContext could each extend MutableProperties and Configuration could extend Properties.