Documentation: Numpy Support

I generally found out that we don't really emphasize that we have Numpy support for interoperability between some Qt class methods i.e. numpy array can be passed as arguments to these functions.

Although these functions have Python docstrings, should we include them somewhere in the overall Qt for Python documentation. Also, including a little bit of details of how Numpy support works in Shiboken (just like pybind11 does it).