[Reqeust] Add more metrics

[svenvg93]

Hi,

first of all I love your exporter. I do have one request, would it be possible to add all the metrics that the json returns. Like the Download and Upload latency

}, "download": { "bandwidth": 11828190, "bytes": 42736320, "elapsed": 3610, "latency": { "iqm": 15.486, "low": 5.905, "high": 26.728, "jitter": 1.256 } }, "upload": { "bandwidth": 116363418, "bytes": 466194584, "elapsed": 4013, "latency": { "iqm": 6.570, "low": 4.289, "high": 7.797, "jitter": 0.435 } }, "packetLoss": 0, "isp": "T-Mobile Netherlands", "interface": { "internalIp": "192.168.0.110", "name": "eno1", "macAddr": "A8:A1:59:0F:5E:E5", "isVpn": false, "externalIp": "82.173.xxxxx }, "server": { "id": 52365, "host": "speedtest.ams.t-mobile.nl", "port": 8080, "name": "Odido", "location": "Amsterdam", "country": "Netherlands", "ip": "37.143xxxxx"