Monitoring improvement for TiDB

[DanielZhangQD]

Feature Request

Is your feature request related to a problem? Please describe:

For TiDB clusters deployed with TiUP and Ansible, there are some extra dashboards in https://github.com/pingcap/monitoring/tree/master/platform-monitoring/ansible/grafana, and it's better to have them with TiDB Operator. Describe the feature you'd like:

Describe alternatives you've considered:

Teachability, Documentation, Adoption, Migration Strategy: