sentinel是否能集成promethues

## Issue Description
sentinel本身有资源的监控数据，目前是否集成了promethues

### Describe what happened (or what feature you want)
想讲sentinel的监控数据，通过promethues进行采集。

### Describe what you expected to happen
sentinel提供promethues-exporter，或者有接口api能提供promethues采集的数据。

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

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### Tell us your environment

### Anything else we need to know?

No files, tests, or entry points are named. Start by reviewing Sentinel's existing resource monitoring data and determine whether the intended scope is a Prometheus exporter, a scrapeable API, or both. Done means the chosen integration scope is defined and the monitoring data can be collected by Prometheus.

Written by the indexing model from the issue text.