Unify fisheye and omnidir API

[kmilos]

System information (version)

• OpenCV => 4.2.0-dev
• Operating System / Platform => any
• Compiler => any

Detailed description

It would be great to have a matching API for fisheye and omnidirectional cameras. There are a couple of features missing from each to complete the set:

fisheye	omnidir
calibrate	calibrate
distortPoints	n/a
estimateNewCameraMatrixForUndistortRectify	n/a
initUndistortRectifyMap	initUndistortRectifyMap (arg name inconsistent - mltype vs m1type)
projectPoints	projectPoints (missing overload w/ affine mtx)
stereoCalibrate	stereoCalibrate
n/a	stereoReconstruct
stereoRectify	stereoRectify
undistortImage	undistortImage
undistortPoints	undistortPoints