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/opencl/CMakeLists.txt

@@ -0,0 +1,38 @@
+ocv_install_example_src(opencl *.cpp *.hpp CMakeLists.txt)
+
+# cmake 3.1 needed for find_package(OpenCL)
+if(CMAKE_VERSION VERSION_LESS "3.1")
+  message(STATUS "OpenCL samples require CMakes 3.1+")
+  return()
+endif()
+
+set(OPENCV_OPENCL_SAMPLES_REQUIRED_DEPS
+  opencv_core
+  opencv_imgproc
+  opencv_video
+  opencv_imgcodecs
+  opencv_videoio
+  opencv_highgui)
+ocv_check_dependencies(${OPENCV_OPENCL_SAMPLES_REQUIRED_DEPS})
+
+if(NOT BUILD_EXAMPLES OR NOT OCV_DEPENDENCIES_FOUND)
+  return()
+endif()
+
+find_package(OpenCL 1.2 QUIET)
+if(NOT OpenCL_FOUND)
+  message(STATUS "OpenCL samples are skipped: OpenCL SDK is required")
+  return()
+endif()
+
+project(opencl_samples)
+ocv_include_modules_recurse(${OPENCV_OPENCL_SAMPLES_REQUIRED_DEPS})
+ocv_include_directories(${OpenCL_INCLUDE_DIR})
+file(GLOB all_samples RELATIVE ${CMAKE_CURRENT_SOURCE_DIR} *.cpp)
+foreach(sample_filename ${all_samples})
+  ocv_define_sample(tgt ${sample_filename} opencl)
+  ocv_target_link_libraries(${tgt} PRIVATE
+    ${OPENCV_LINKER_LIBS}
+    ${OPENCV_OPENCL_SAMPLES_REQUIRED_DEPS}
+    ${OpenCL_LIBRARY})
+endforeach()