Feature: Make CNSI can be integrated with Prometheus and Grafana.

[4everming]

Is your feature request related to a problem? Please describe.
A clear and concise description of what the problem is. Ex. I'm always frustrated when [...]

Describe the solution you'd like
Some of the Kubernetes users have already deployed things like Prometheus and Grafana in their environment. We'd like to make CNSI be integrated with Prometheus and Grafana so that the security info can be stored in Prometheus and viewed by a user-defined dashboard in Grafana.

Describe the main design/architecture of your solution
The security data generated by CNSI will be abstracted to metric and reported to Prometheus as the metric target periodically.