Add official builds and bit-exactness to opencv.md
OpenCV conformity tests are also updated, as KleidiCV's remap implementation is bit-exact with OpenCV, if map1.type() is CV_16SC2 and map2 is empty.
OpenCV conformity tests are also updated, as KleidiCV's remap implementation is bit-exact with OpenCV, if map1.type() is CV_16SC2 and map2 is empty.