Merge pull request #25075 from mshabunin:cleanup-imgproc-1

C-API cleanup: apps, imgproc_c and some constants #25075

Merge with https://github.com/opencv/opencv_contrib/pull/3642

* Removed obsolete apps - traincascade and createsamples (please use older OpenCV versions if you need them). These apps relied heavily on C-API
* removed all mentions of imgproc C-API headers (imgproc_c.h, types_c.h) - they were empty, included core C-API headers
* replaced usage of several C constants with C++ ones (error codes, norm modes, RNG modes, PCA modes, ...) - most part of this PR (split into two parts - all modules and calib+3d - for easier backporting)
* removed imgproc C-API headers (as separate commit, so that other changes could be backported to 4.x)

Most of these changes can be backported to 4.x.

modules/core/src/dxt.cpp

@@ -3469,7 +3469,7 @@ Ptr<DFT2D> DFT2D::create(int width, int height, int depth,
     {
         if(width == 1 && nonzero_rows > 0 )
         {
-            CV_Error( CV_StsNotImplemented,
+            CV_Error( cv::Error::StsNotImplemented,
             "This mode (using nonzero_rows with a single-column matrix) breaks the function's logic, so it is prohibited.\n"
             "For fast convolution/correlation use 2-column matrix or single-row matrix instead" );
         }
@@ -4317,7 +4317,7 @@ public:
             if( len != prev_len )
             {
                 if( len > 1 && (len & 1) )
-                    CV_Error( CV_StsNotImplemented, "Odd-size DCT\'s are not implemented" );
+                    CV_Error( cv::Error::StsNotImplemented, "Odd-size DCT\'s are not implemented" );
 
                 opt.nf = DFTFactorize( len, opt.factors );
                 bool inplace_transform = opt.factors[0] == opt.factors[opt.nf-1];