Revert back to CRD terminology vs. certificates

[james-ball-qualcomm]

Now that I've thought this through better (see slides at https://docs.google.com/presentation/d/1dc7-uWNIHd6qMNlhWxfwCnzACQaSL2vfkHqP_qdpkac and screenshot of key slide below), I need to go back to having what is currently called certificate_models to CRD somehow.

[james-ball-qualcomm]

Just going to rename the backend generator to CRD. The /arch files can stay unchanged.

[james-ball-qualcomm]

Also going to add "Processor" prefix to Certificate Class/Model to support non-processor certificates that don't follow this class/model naming scheme.