Add command for scanning 868 MHz sensors

[matthias-bs]

To find your sensors (or other sensors within range) you currently have to run BresserWeatherSensorBasic or BresserWeatherSensorLW with debugging enabled and USB connection to serial console for analysis .

This feature will allow to get the same information via LoRaWAN.

CMD_SENSORS_SCAN <scan_time>

Resonse:

<id0>, <decoder0>, <type0>, <ch0>[, <flags0>], <rssi0>
...
<idN>, <decoderN>, <typeN>, <chN>[, <flagsN>], <rssiN>

[matthias-bs]

Request:

{"ws_scantime": 180}

Response (raw) - 48 bytes:

792882A211000C6422400873130100343958237611001F4E0000EEFB3900006B6756630014010060289667964503006A

Response (decoded):

"found_sensors": [
            {
              "ch": 0,
              "decoder": "6-in-1",
              "flags": "0x0c",
              "id": "0x792882a2",
              "rssi": -100,
              "type": "Weather Sensor"
            },
            {
              "ch": 1,
              "decoder": "6-in-1",
              "flags": "0x00",
              "id": "0x22400873",
              "rssi": -52,
              "type": "Pool / Spa Thermometer"
            },
            {
              "ch": 0,
              "decoder": "6-in-1",
              "flags": "0x1f",
              "id": "0x39582376",
              "rssi": -78,
              "type": "Weather Sensor"
            },
            {
              "ch": 0,
              "decoder": "Lightning",
              "flags": "0x00",
              "id": "0x0000eefb",
              "rssi": -107,
              "type": "Lightning Sensor"
            },
            {
              "ch": 1,
              "decoder": "6-in-1",
              "flags": "0x00",
              "id": "0x67566300",
              "rssi": -96,
              "type": "Soil Temperature and Moisture Sensor"
            },
            {
              "ch": 3,
              "decoder": "Leakage",
              "flags": "0x00",
              "id": "0x28966796",
              "rssi": -106,
              "type": "Water Leakage Sensor"
            }
          ]