Add Affinity Router

[wcy666103]

What is the purpose of the change?

Add affinity router rule v3.1 refer here #14455

Brief changelog

dubbo/config/group/{$name}.affinity-router

configVersion: v3.1
scope: service # Or application
key: service.apache.com
enabled: true
runtime: true
affinityAware:
  key: region
  ratio: 20

Checklist

• Make sure there is a GitHub_issue field for the change.
• Write a pull request description that is detailed enough to understand what the pull request does, how, and why.
• Write necessary unit-test to verify your logic correction. If the new feature or significant change is committed, please remember to add sample in dubbo samples project.
• Make sure gitHub actions can pass. Why the workflow is failing and how to fix it?