add opentsdb based metric store .

## Issue Description

Type: *bug report* or *feature request*

### Describe what happened (or what feature you want)
in order to see history metric , persist history metric data in opentsdb (Time series database ) for performance reason

### Describe what you expected to happen
see history metric result use dashboard

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

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### Tell us your environment
jdk 1.8
maven 3.6
linux
### Anything else we need to know?

The issue names no files, tests, or entry points. Start by locating Sentinel's existing metric-history persistence and dashboard paths, then define the OpenTSDB integration and verify that historical metric results appear in the dashboard.

Written by the indexing model from the issue text.