HA Discovery as different device type

[beerygaz]

I have a few shutter/blind controllers that use a group for up/down/stop - it would be great if cmqttd could publish the device type as "cover" instead of "light". The only way I can think of achieving this would be to have a text file that mapped groups to HA device types (this would enable the "switch" type and "button" type too which may be useful?)