refactored feedback & its depending stuff

- buzzer is just modulate_tone
- led is just turn on and off
- handle feedback logic to feeback file

src/main.rs

@@ -21,7 +21,6 @@ use mock::MockHotspot;
 
 mod activity_fairing;
 mod buzzer;
-mod color;
 mod feedback;
 mod hotspot;
 mod id_mapping;