统一下单支付

这是对QQ小程序开发者文档-微信支付 的一个封装. 目的是独立权限集

请求地址

1. V2版H5支付: https://api.q.qq.com/api/component/wxpay/unifiedorder?access_token=ACCESS_TOKEN
2. V3版H5下单API（直连模式）: https://api.q.qq.com/api/component/wxpay/v3/pay/transactions/h5?access_token=ACCESS_TOKEN
3. V3版H5下单API（服务商模式): https://api.q.qq.com/api/component/wxpay/v3/pay/partner/transactions/h5?access_token=ACCESS_TOKEN
4. V3版合单支付API: https://api.q.qq.com/api/component/wxpay/v3/combine-transactions/h5?access_token=ACCESS_TOKEN