Add modern cmake style CMakeLists.txt

[yangxiang92]

Add modern cmake style CMakeLists.txt so that other modules can refer to it by simply using add_subdirectory or find_package.

e.g.

add_subdirectory(third_party/QtOpenCV)
target_link_libraries(${PROJECT_NAME} PRIVATE QtOpenCV)

or

find_package(QtOpenCV REQUIRED)
target_link_libraries(${PROJECT_NAME} PRIVATE QtOpenCV)