获取节点费率

URL: 
/api/project/fee

METHOD: 
GET

RESULT:
[
    {
        "r": "0.01",     // 费率 需要x100得到百分比
        "coin": "BTC"    // 币种
    },
    {
        "r": "0.01",
        "coin": "FB"
    },
    {
        "r": "0.01",
        "coin": "KAS"
    },
    ...
]