add drone status node

src/drone_services/msg/DroneArmStatus.msg

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+bool armed false

src/drone_services/msg/DroneRouteStatus.msg

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+int32 current_setpoint_index
+float32[5] current_setpoint # x,y,z,angle,take_picture

src/drone_services/msg/DroneStatus.msg

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+float32 battery_percentage
+float32 cpu_usage
+int32 route_setpoint # -1 if no route
+wstring control_mode
+bool armed