NetApp Cinder driver refactoring, phase 1

NetApp's five Cinder drivers have been in continuous development for nearly 3 years, and it would seem necessary to do some housecleaning. The first phase will include splitting long files that contain multiple classes, normalizing the class hierarchies to enable subclassing different driver classes (ISCSIDriver, FibreChannelDriver), and renaming classes. Later phases will move unit test files into a matching hierarchy in the "tests" tree, improve SDK usage, standardize data motion tasks, and generally clean up existing code; separate blueprints will be submitted for those.