Add the Grafana dashboard

[zyy17]

What problem does the new feature solve?

We should add and maintain the Granfana dashboard in the community for better observability. By using the dashboard, we can know the health status of greptimedb(standalone or cluster). According to the metrics, we also can use it to create the alert rules.

What does the feature do?

In my opinion, the dashboard should contain:

• The greptimedb overview, including version/cluster size/mode etc.
• The important metrics of different services(frontend/meta/datanode)
• Maintain the dashboard as code
• Add the CI to submit to Grafana Dashboard, and the greptimedb user can just import the dashboard by dashboard ID;

Implementation challenges

No response

[zyy17]

Close for duplicated issue: #3262.