获取币种算力、设备数量列表

URL: 
/api/coin/hashrate

METHOD: 
GET

RESULT:
[
    {
        "coin": "BTC",
        "hashrate": "1.355771137822993e15",
        "offline": "0",
        "online": "7"
    },
    {
        "coin": "KAS",
        "hashrate": "4277000000000",
        "offline": "0",
        "online": "1"
    }
]