hide highgui in opencv_core, opencv_dart, remove submodule

Author: rainyl

.gitmodules

@@ -1,4 +0,0 @@
-[submodule "packages/dartcv/src"]
-	path = packages/dartcv/src
-	url = https://github.com/rainyl/dartcv.git
-	branch = main

packages/opencv_core/lib/opencv.dart

@@ -5,4 +5,15 @@
 /// OpenCV bindings for Flutter
 library cv;
 
-export 'package:dartcv4/dartcv.dart';
+export 'package:dartcv4/calib3d.dart';
+export 'package:dartcv4/contrib.dart';
+export 'package:dartcv4/core.dart';
+export 'package:dartcv4/dnn.dart';
+export 'package:dartcv4/features2d.dart';
+export 'package:dartcv4/imgcodecs.dart';
+export 'package:dartcv4/imgproc.dart';
+export 'package:dartcv4/objdetect.dart';
+export 'package:dartcv4/photo.dart';
+export "package:dartcv4/src/g/constants.g.dart";
+export 'package:dartcv4/stitching.dart';
+export 'package:dartcv4/video.dart';

packages/opencv_dart/lib/opencv.dart

@@ -5,4 +5,16 @@
 /// OpenCV bindings for Flutter
 library cv;
 
-export 'package:dartcv4/dartcv.dart';
+export 'package:dartcv4/calib3d.dart';
+export 'package:dartcv4/contrib.dart';
+export 'package:dartcv4/core.dart';
+export 'package:dartcv4/dnn.dart';
+export 'package:dartcv4/features2d.dart';
+export 'package:dartcv4/imgcodecs.dart';
+export 'package:dartcv4/imgproc.dart';
+export 'package:dartcv4/objdetect.dart';
+export 'package:dartcv4/photo.dart';
+export "package:dartcv4/src/g/constants.g.dart";
+export 'package:dartcv4/stitching.dart';
+export 'package:dartcv4/video.dart';
+export 'package:dartcv4/videoio.dart';