Make C++ level device interface generic (device agnostic)

[dvrogozh]

See: src/torchcodec/decoders/_core/DeviceInterface.h

Currently defined device interface is CUDA specific by naming and usage. As discussed in #559 (comment) this complicates adding support for other device backends. It does seem a right step to refactor device interface, make it generic and allow easy registration of non-CUDA device specific backends. Creating this issue to track that.

CC: @scotts, @NicolasHug