Add conditions in the Pipeline status

Conditions will be a good way to record the status of a Pipeline. Such as failed to delete a Pipeline due to the Jenkins is not reachable.

```
status:
conditions:
reason: 'Jenkins is not reachable'
```

## References
* https://github.com/kubesphere/ks-devops/blob/master/controllers/pipeline/pipeline_controller.go

Start with controllers/pipeline/pipeline_controller.go and inspect how Pipeline status is currently updated. Trace the deletion failure path and determine how the status conditions should record that Jenkins is unreachable. Done means the Pipeline status exposes the requested condition with the failure reason and the relevant behavior is covered by the repository's existing tests, if applicable.

Written by the indexing model from the issue text.