[TESTING] Unittest Suite Init

Come up with a simple framework for unit-testing and automation

-- Update --

For now, try to add unitest suited for CNC as an experiment.

• Focusing on flow check (e.g. check when takeoff is called, the correct package is built and sent to ROS. some expect call checking)
• Don't worry about automation test with SITL simulation for now :)

-- Update --

Refactor and unit test suite sample is in. XD

You can try to add some tests to Command test group.

Note: we are NOT going to unit test any HWI components (except for safety features and checks)