[Feature] support monitor for doris

### Search before asking

- [x] I had searched in the [issues](https://github.com/apache/doris-operator/issues?q=is%3Aissue) and found no similar issues.

### Description

## Background
Doris collects monitor metrics by itself, in prometheus format. you can fetch monitor data from Doris HTTP service.
The interface as follows:
Frontend: fe_host:fe_http_port/metrics
Backend: be_host:be_web_server_port/metrics
But, in kubernetes prometheus uses `ServiceMonitor` as a common mode to collect doris metrics. DorisCluster should add a switch to generate a ServiceMonitor resource to prometheus for collecting metrics in doris.

## How to use
If you want promtheus deployed by prometheus-operator to pull metrics from doris, please add last config in DorisCluster resource:
```
spec:
enableServiceMonitor: true
```
doris-operator will generate a `ServiceMonitor` in the namespace where DorisCluster deployed.

### Use case

_No response_

### Related issues

_No response_

### Are you willing to submit PR?

- [x] Yes I am willing to submit a PR!

### Code of Conduct

- [x] I agree to follow this project's [Code of Conduct](https://www.apache.org/foundation/policies/conduct)