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/videoio/src/cap_ffmpeg_legacy_api.hpp

@@ -0,0 +1,46 @@
+// This file is part of OpenCV project.
+// It is subject to the license terms in the LICENSE file found in the top-level directory
+// of this distribution and at http://opencv.org/license.html.
+#ifndef __OPENCV_FFMPEG_LEGACY_API_H__
+#define __OPENCV_FFMPEG_LEGACY_API_H__
+
+#ifdef __cplusplus
+extern "C"
+{
+#endif
+
+#ifndef OPENCV_FFMPEG_API
+#if defined(__OPENCV_BUILD)
+#   define OPENCV_FFMPEG_API
+#elif defined _WIN32
+#   define OPENCV_FFMPEG_API __declspec(dllexport)
+#elif defined __GNUC__ && __GNUC__ >= 4
+#   define OPENCV_FFMPEG_API __attribute__ ((visibility ("default")))
+#else
+#   define OPENCV_FFMPEG_API
+#endif
+#endif
+
+typedef struct CvCapture_FFMPEG CvCapture_FFMPEG;
+typedef struct CvVideoWriter_FFMPEG CvVideoWriter_FFMPEG;
+
+//OPENCV_FFMPEG_API struct CvCapture_FFMPEG* cvCreateFileCapture_FFMPEG(const char* filename);
+OPENCV_FFMPEG_API int cvSetCaptureProperty_FFMPEG(struct CvCapture_FFMPEG* cap,
+                                                  int prop, double value);
+OPENCV_FFMPEG_API double cvGetCaptureProperty_FFMPEG(struct CvCapture_FFMPEG* cap, int prop);
+OPENCV_FFMPEG_API int cvGrabFrame_FFMPEG(struct CvCapture_FFMPEG* cap);
+OPENCV_FFMPEG_API int cvRetrieveFrame_FFMPEG(struct CvCapture_FFMPEG* capture, unsigned char** data,
+                                             int* step, int* width, int* height, int* cn);
+OPENCV_FFMPEG_API void cvReleaseCapture_FFMPEG(struct CvCapture_FFMPEG** cap);
+
+OPENCV_FFMPEG_API struct CvVideoWriter_FFMPEG* cvCreateVideoWriter_FFMPEG(const char* filename,
+            int fourcc, double fps, int width, int height, int isColor );
+OPENCV_FFMPEG_API int cvWriteFrame_FFMPEG(struct CvVideoWriter_FFMPEG* writer, const unsigned char* data,
+                                          int step, int width, int height, int cn, int origin);
+OPENCV_FFMPEG_API void cvReleaseVideoWriter_FFMPEG(struct CvVideoWriter_FFMPEG** writer);
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif  // __OPENCV_FFMPEG_LEGACY_API_H__