Add Gtest

[RachelRen05]

1. Prerequisites to successfully run movidius_ncs_lib test is that compilation of Supported CNN Models. You can refer:https://github.com/intel/ros2_intel_movidius_ncs#5-running-the-demo
2. Please launch realsense_ros2_camera node before run movidius_ncs_stream test.Absolutely this is a temporary solution.