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/samples/dnn/CMakeLists.txt

@@ -0,0 +1,24 @@
+ocv_install_example_src(dnn *.cpp *.hpp CMakeLists.txt)
+
+set(OPENCV_DNN_SAMPLES_REQUIRED_DEPS
+  opencv_core
+  opencv_imgproc
+  opencv_dnn
+  opencv_objdetect
+  opencv_video
+  opencv_imgcodecs
+  opencv_videoio
+  opencv_highgui)
+ocv_check_dependencies(${OPENCV_DNN_SAMPLES_REQUIRED_DEPS})
+
+if(NOT BUILD_EXAMPLES OR NOT OCV_DEPENDENCIES_FOUND)
+  return()
+endif()
+
+project(dnn_samples)
+ocv_include_modules_recurse(${OPENCV_DNN_SAMPLES_REQUIRED_DEPS})
+file(GLOB_RECURSE dnn_samples RELATIVE ${CMAKE_CURRENT_SOURCE_DIR} *.cpp)
+foreach(sample_filename ${dnn_samples})
+  ocv_define_sample(tgt ${sample_filename} dnn)
+  ocv_target_link_libraries(${tgt} PRIVATE ${OPENCV_LINKER_LIBS} ${OPENCV_DNN_SAMPLES_REQUIRED_DEPS})
+endforeach()