Configure node_exporter metric support

When scrape Prometheus metrics, maybe there are too many metrics scraped and I want some filter plugin can filter out unwanted metrics. (the grep plugin filter only work with JSON format)

## **Proposal**
Config value "Include/Exclude" have multi values, or have regex strings.
**Metric filter**
```
[FILTER]
Name metrics
Match node_exporter*
Include node_memory*,node_cpu_seconds*
```