Add `tasks.<TASKNAME>.podName` to DAG Templates

[yoogoc]

Summary

Add tasks.<TASKNAME>.podName to DAG Templates

Add steps.<TASKNAME>.podName to Steps Templates

Use Cases

1. The default key for artifact is {{workflow.name}}/{{pod.name}}/< NAME >. If it is added, then this key can be concatenated in other tasks.
2. other tasks need read pod name of previous task

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