Fix typo in js_tutorials

* Adding constants to json file

* adding sub-module to constants name

* adding namespace to functions

* adding namespace to classes

* remove namespace from methods

* static methods

* python signatures generation

* python: more fixes for signatures generation

Python names existence can be checked via command:

    python -c "import cv2 as cv; print(repr(<py_name>))"

for non-ANDROID platforms

Flush deallocation queue before calling map/unmap

Resolves - https://github.com/opencv/opencv/issues/9928