p_qps and b_qps are not intuitive in monitoring curve of dashboard

[sczyh30]

Issue Description

Type: enhancement

Describe what happened (or what feature you want)

p_qps and b_qps are not intuitive in monitoring curve of Sentinel dashboard.

Sentinel 控制台中实时监控曲线中的 p_qps 和 b_qps 描述不直观。

Describe what you expected to happen

p_qps, b_qps, rt 可以换成更直观的描述：通过 QPS，拒绝 QPS，响应时间（ms）。