Merge pull request #24773 from tailsu:sd/pathlike

python: accept path-like objects wherever file names are expected #24773

Merry Christmas, all 🎄

Implements #15731

Support is enabled for all arguments named `filename` or `filepath` (case-insensitive), or annotated with `CV_WRAP_FILE_PATH`.

Support is based on `PyOS_FSPath`, which is available in Python 3.6+. When running on older Python versions the arguments must have a `str` value as before.

### Pull Request Readiness Checklist

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

- [x] I agree to contribute to the project under Apache 2 License.
- [x] To the best of my knowledge, the proposed patch is not based on a code under GPL or another license that is incompatible with OpenCV
- [x] The PR is proposed to the proper branch
- [x] There is a reference to the 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

modules/core/include/opencv2/core/cvdef.h

@@ -475,6 +475,8 @@ Cv64suf;
 #define CV_WRAP_MAPPABLE(mappable)
 #define CV_WRAP_PHANTOM(phantom_header)
 #define CV_WRAP_DEFAULT(val)
+/* Indicates that the function parameter has filesystem path semantic */
+#define CV_WRAP_FILE_PATH
 
 /****************************************************************************************\
 *                                  Matrix type (Mat)                                     *