[G-API]: fitLine() Standard Kernel Implementation * fitLine API (Mat, 32S, 32F) (2D, 3D) * Complete fitLine kernel & accuracy tests - initialization for vectors of cv::Point and Mats via vectors added - comparison functions for Vec<T, n> added: - straight average difference comparison - comparison by equasion for 2d line - stream overload for cv::DistanceTypes added * Fix precommit warnings * Fix docs * Address comments Try to fix warning * Disable warning in tests