Fix cudacodec python

* Add python bindings to cudacodec.

* Allow args with CV_OUT GpuMat& or CV_OUT cuda::GpuMat& to generate python bindings that allow the argument to be an optional output in the same way as OutputArray.

* Add wrapper flag to indicate that an OutputArray is a GpuMat.

* python: drop CV_GPU, extra checks in test

* Remove "cuda::GpuMat" check rom python parser