Add applianceSupplyTemperature

[JosefRypacek]

Hi, I have IVT heat pump and use HA integration which works, but it's missing applianceSupplyTemperature (warm water from heat pump to the radiators/boiler). The HA integration already contains return temperature (the colder water which returns from radiators/boiler to the heat pump).

My heat pump identifies itself as follows, so I hope I made this PR correct.

        {
            "id": "/gateway/versionFirmware",
            "type": "stringValue",
            "writeable": 0,
            "recordable": 0,
            "value": "04.08.02"
        },
        {
            "id": "/gateway/versionHardware",
            "type": "stringValue",
            "writeable": 0,
            "recordable": 0,
            "value": "iCom_Low_NSC_v1"
        },