Feature: A cluster overall risk score should be showed to users.

[4everming]

Is your feature request related to a problem? Please describe.
No

Describe the solution you'd like
Cluster overall risk score is a weighted summary of different individual risk factors including vulnerabilities, misconfigurations, scanning coverage, and violations.

Describe the main design/architecture of your solution
The scanning results that contain the vulnerabilities, misconfigurations and other security information will be gathered periodically. Each factor will have a default weight in order to compute the cluster overall risk score.

Describe the development plan you've considered
Plan to deliver this feature in the first release by the end of November 2022.

Additional context
Add any other context or screenshots about the feature request here.