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/misc/java/test/TrackerCreateTest.java

@@ -0,0 +1,32 @@
+package org.opencv.test.video;
+
+import org.opencv.core.Core;
+import org.opencv.core.CvException;
+import org.opencv.test.OpenCVTestCase;
+
+import org.opencv.video.Tracker;
+import org.opencv.video.TrackerGOTURN;
+import org.opencv.video.TrackerMIL;
+
+public class TrackerCreateTest extends OpenCVTestCase {
+
+    @Override
+    protected void setUp() throws Exception {
+        super.setUp();
+    }
+
+
+    public void testCreateTrackerGOTURN() {
+        try {
+            Tracker tracker = TrackerGOTURN.create();
+            assert(tracker != null);
+        } catch (CvException e) {
+            // expected, model files may be missing
+        }
+    }
+
+    public void testCreateTrackerMIL() {
+        Tracker tracker = TrackerMIL.create();
+    }
+
+}