Users want to set one alert for the error rate by query type.

## Feature Request

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

Users want to set one alert for the error rate by query type.

**Describe the feature you'd like:**

Add DML types on the metric of `tidb_executor_statement`. Users can use PQL to set the alert related to query type on the Grafana metric and alert notification.

**Describe alternatives you've considered:**

N/A
**Teachability, Documentation, Adoption, Migration Strategy:**