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/ncnn/tools/caffe/CMakeLists.txt

@@ -0,0 +1,18 @@
+
+find_package(Protobuf)
+
+if(PROTOBUF_FOUND)
+    protobuf_generate_cpp(CAFFE_PROTO_SRCS CAFFE_PROTO_HDRS caffe.proto)
+    add_executable(caffe2ncnn caffe2ncnn.cpp ${CAFFE_PROTO_SRCS} ${CAFFE_PROTO_HDRS})
+    target_include_directories(caffe2ncnn
+        PRIVATE
+            ${PROTOBUF_INCLUDE_DIR}
+            ${CMAKE_CURRENT_BINARY_DIR})
+    target_link_libraries(caffe2ncnn PRIVATE ${PROTOBUF_LIBRARIES})
+
+    # add all caffe2ncnn tool to a virtual project group
+    set_property(TARGET caffe2ncnn PROPERTY FOLDER "tools/converter")
+    ncnn_install_tool(caffe2ncnn)
+else()
+    message(WARNING "Protobuf not found, caffe model convert tool won't be built")
+endif()