Display HS300 as one power strip device rather than six individual plugs
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### Expected Behavior
The HS300 should appear as one device with six controllable outlets.
Native HomeKit powerstrips, like the Koogeek strip, appear as a single device.

### Current Behavior
The six plugs on an HS300 appear as individual switches. Grouping them in HomeKit prevents them from being controlled individually.

### Version
Homebridge 1.3.1
homebridge-tplink-smarthome 6.1.0
