Expose DescriptorRegistry as a service

Every component implementation extending DefaultComponent have access to the instance of DescriptorRegistry, still there is no dedicated interface to contribute to the descriptor.

It would be easy to define a DescriptorService that would allow this.

/ ! \ Component life cycle has to be studied and may have to be adapted to handle this behavior since for now the recommended good practice is to consume descriptors on start() that would not be called using this way to contribute / ! \