希望热点参数限流，可以针对请求头里的参数进行限流

## Issue Description
希望热点参数限流，可以针对请求头里的参数进行限流

Type: *feature request*

### Describe what happened (or what feature you want)
经常使用的场景就是，业务比如希望针对某个用户、或者某个IP+用户可以限制访问，1分钟10次或者多少次。

### Describe what you expected to happen
目前通过原生的能力无法满足

### How to reproduce it (as minimally and precisely as possible)

### Tell us your environment

### Anything else we need to know?

The issue names no files, tests, or entry points. Begin by reviewing Sentinel's existing hotspot-parameter rate-limiting capabilities and how request headers are represented, then clarify the supported user/IP combinations, configuration model, and acceptance tests before implementation.

Written by the indexing model from the issue text.