Allow cv::cuda::Event to accept combinations of flags as implied by the Nvidia docs:

• cudaEventDisableTiming: Specifies that the created event does not need to record timing data. Events created with this flag specified and the cudaEventBlockingSync flag not specified will provide the best performance when used with cudaStreamWaitEvent() and cudaEventQuery().

• cudaEventInterprocess: Specifies that the created event may be used as an interprocess event by cudaIpcGetEventHandle(). cudaEventInterprocess must be specified along with cudaEventDisableTiming.

Currently there are no event tests, these have been added to opencv/opencv_contrib#3144.

Additionaly there are currently two Event and Stream classes inside the repo, one inside cv::cuda and one inside cv::dnn::cuda4dnn::csl. Is there any requirement to merge them or have them inherit from the same base class?

Pull Request Readiness Checklist

See details at https://github.com/opencv/opencv/wiki/How_to_contribute#making-a-good-pull-request

• I agree to contribute to the project under Apache 2 License.
• To the best of my knowledge, the proposed patch is not based on a code under GPL or other license that is incompatible with OpenCV
• The PR is proposed to proper branch
• There is reference to original bug report and related work
• There is accuracy test, performance test and test data in opencv_extra repository, if applicable
  Patch to opencv_extra has the same branch name.
• The feature is well documented and sample code can be built with the project CMake

opencv_contrib=test_cuda_event
force_builders=Custom
buildworker:Custom=linux-4,linux-6
Xbuild_image:Custom=ubuntu-cuda:18.04
build_image:Custom=ubuntu-cuda-cc52:18.04