Extend Datadog metrics

### Is your proposal related to a problem?

Currently, we have the limited list of Datadog metrics (see the screenshot)

### Describe the solution you'd like

In order to get more visibility, we would like to get:
- Remote service (RxV) latency
- Remote service errors/success
- Hasura service latency
- Hasura service errors/success
- Remove service retries count (if Hasura does retries)
- PG query latency
- PG functions latency, tagged w/ function name
- Hasura cache hits/miss, tagged w/ GQL operation/subscription name
- Triggers latency, tagged w/ trigger name
- Triggers errors/success, tagged w/ trigger name

### Describe alternatives you've considered

### If the feature is approved, would you be willing to submit a PR?