Merge pull request #25970 from savuor:rv/hal_pyrdown

pyrDown: offset HAL added, IPP removed #25970

Resolves #25976

### Changes
* HAL added for offset support so that border pixels can be fetched from outside of the image ROI (see `BORDER_ISOLATED` parameter)
* IPP removed since there is `pyrUp` instead of `pyrDown` and there's no easy way to fix this other than rewriting it from scratch
* replaced old C call by modern `cv::pyrDown`

### 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
- [ ] There is a reference to the original bug report and related work
- [x] There is accuracy test, performance test and test data in opencv_extra repository, if applicable
      Patch to opencv_extra has the same branch name.
- [x] The feature is well documented and sample code can be built with the project CMake

modules/imgproc/src/hal_replacement.hpp

@@ -1247,6 +1247,33 @@ inline int hal_ni_pyrdown(const uchar* src_data, size_t src_step, int src_width,
 #define cv_hal_pyrdown hal_ni_pyrdown
 //! @endcond
 
+/**
+   @brief Perform Gaussian Blur and downsampling for input tile with optional margins for submatrix
+   @param src_data Source image data
+   @param src_step Source image step
+   @param src_width Source image width
+   @param src_height Source image height
+   @param dst_data Destination image data
+   @param dst_step Destination image step
+   @param dst_width Destination image width
+   @param dst_height Destination image height
+   @param depth Depths of source and destination image
+   @param cn Number of channels
+   @param margin_left Left margins for source image
+   @param margin_top Top margins for source image
+   @param margin_right Right margins for source image
+   @param margin_bottom Bottom margins for source image
+   @param border_type Border type
+*/
+inline int hal_ni_pyrdown_offset(const uchar* src_data, size_t src_step, int src_width, int src_height,
+                                 uchar* dst_data, size_t dst_step, int dst_width, int dst_height,
+                                 int depth, int cn, int margin_left, int margin_top, int margin_right, int margin_bottom, int border_type)
+{ return CV_HAL_ERROR_NOT_IMPLEMENTED; }
+
+//! @cond IGNORED
+#define cv_hal_pyrdown_offset hal_ni_pyrdown_offset
+//! @endcond
+
 /**
    @brief Canny edge detector
    @param src_data Source image data