Deprecate CUDA packages

[psyhtest]

Caffe used to support three modes: CPU, CUDA (cuBLAS) and cuDNN. They seems to have dropped cuBLAS support, so there are only two options:

caffe_option(CPU_ONLY  "Build Caffe without CUDA support" OFF) # TODO: rename to USE_CUDA
caffe_option(USE_CUDNN "Build Caffe with cuDNN library support" ON IF NOT CPU_ONLY)

Therefore, the CUDA packages are the same as the cuDNN ones, so we should deprecate them. To avoid confusion and for consistency with CK-TensorFlow, we should then rename cudnn packages to cuda.

[gfursin]

Wait, but someone may still want to check older versions/technology? How will they be able to do that if you remove such packages?