Organization of the source code for the wrappers

[ViralBShah]

Currently, the way we build this package is that opencv and opencv-contrib are both recipes in the Yggdrasil repo. The code in contrib generates the wrappers for the Julia package.

It probably would be better to have the contrib stuff in this repo and generate the julia wrapper code independent of the opencv binary build. I do not know if it has dependencies on the opencv build process itself. Just thought I would leave it here.

@barche Any thoughts on this based on your recent experience?

[barche]

I would proceed as follows:

• move all Julia code out of opencv_contrib and into this repository
• keep the c++ code in opencv_contrib to ensure compatibility with the corresponding OpenCV

From what I can see most of the C++ is generated from within the OpenCV build system, so it’s easier to leave it there.