Allow developers programmatic access to actuator categorisation metadata

Currently, actuators are returned in the API as a "flat list", and no categorisation information is available to developers.
It would be useful for developers if they could say: "get me a vibra actuator", or perhaps "I want this feedback effect to be performed by the touchscreen piezo" instead of having to manually test each available actuator on each device they are targeting, and hardcoding which actuator to use on each device.