Merge pull request #18838 from alalek:video_tracking_api

Tracking API: move to video/tracking.hpp

* video(tracking): moved code from opencv_contrib/tracking module

- Tracker API
- MIL, GOTURN trackers
- applied clang-format

* video(tracking): cleanup unused code

* samples: add tracker.py sample

* video(tracking): avoid div by zero

* static analyzer

modules/video/test/test_main.cpp

@@ -7,4 +7,19 @@
     #include <hpx/hpx_main.hpp>
 #endif
 
-CV_TEST_MAIN("cv")
+static
+void initTests()
+{
+    const char* extraTestDataPath =
+#ifdef WINRT
+        NULL;
+#else
+        getenv("OPENCV_DNN_TEST_DATA_PATH");
+#endif
+    if (extraTestDataPath)
+        cvtest::addDataSearchPath(extraTestDataPath);
+
+    cvtest::addDataSearchSubDirectory("");  // override "cv" prefix below to access without "../dnn" hacks
+}
+
+CV_TEST_MAIN("cv", initTests())