feat: 切换后端至PaddleOCR-NCNN，切换工程为CMake

1.项目后端整体迁移至PaddleOCR-NCNN算法，已通过基本的兼容性测试
2.工程改为使用CMake组织，后续为了更好地兼容第三方库，不再提供QMake工程
3.重整权利声明文件，重整代码工程，确保最小化侵权风险

Log: 切换后端至PaddleOCR-NCNN，切换工程为CMake
Change-Id: I4d5d2c5d37505a4a24b389b1a4c5d12f17bfa38c

3rdparty/opencv-4.5.4/modules/highgui/misc/plugins/build_plugins.sh

@@ -0,0 +1,72 @@
+#!/bin/bash
+
+set -e
+
+if [ -z $1 ] ; then
+    echo "$0 <destination directory>"
+    exit 1
+fi
+
+DIR="$( cd "$( dirname "${BASH_SOURCE[0]}" )" >/dev/null 2>&1 && pwd )"
+OCV="$( cd "${DIR}/../../../.." >/dev/null 2>&1 && pwd )"
+mkdir -p "${1}"  # Docker creates non-existed mounts with 'root' owner, lets ensure that dir exists under the current user to avoid "Permission denied" problem
+DST="$( cd "$1" >/dev/null 2>&1 && pwd )"
+CFG=${2:-Release}
+
+do_build()
+{
+TAG=$1
+D=$2
+F=$3
+shift 3
+docker build \
+    --build-arg http_proxy \
+    --build-arg https_proxy \
+    $@ \
+    -t $TAG \
+    -f "${D}/${F}" \
+    "${D}"
+}
+
+do_run()
+{
+TAG=$1
+shift 1
+docker run \
+    -it \
+    --rm \
+    -v "${OCV}":/opencv:ro \
+    -v "${DST}":/dst \
+    -e CFG=$CFG \
+    --user $(id -u):$(id -g) \
+    $TAG \
+    "$@"
+}
+
+build_gtk2_ubuntu()
+{
+VER=$1
+shift 1
+TAG=opencv_highgui_ubuntu_gtk2_builder:${VER}
+do_build $TAG "${DIR}/plugin_gtk" Dockerfile-ubuntu-gtk2 --build-arg VER=${VER}
+do_run $TAG /opencv/modules/highgui/misc/plugins/plugin_gtk/build.sh /dst gtk2_ubuntu${VER} ${CFG} "$@"
+
+}
+
+build_gtk3_ubuntu()
+{
+VER=$1
+shift 1
+TAG=opencv_highgui_ubuntu_gtk3_builder:${VER}
+do_build $TAG "${DIR}/plugin_gtk" Dockerfile-ubuntu-gtk3 --build-arg VER=${VER}
+do_run $TAG /opencv/modules/highgui/misc/plugins/plugin_gtk/build.sh /dst gtk3_ubuntu${VER} ${CFG} "$@"
+}
+
+echo "OpenCV: ${OCV}"
+echo "Destination: ${DST}"
+
+build_gtk2_ubuntu 16.04
+build_gtk2_ubuntu 16.04 -DOPENCV_PLUGIN_NAME=opencv_highgui_gtk2-opengl_ubuntu16.04 -DWITH_OPENGL=ON -DWITH_GTK_2_X=ON
+build_gtk2_ubuntu 18.04
+build_gtk3_ubuntu 18.04
+build_gtk3_ubuntu 20.04