"job describe" should show pod names next to datum ids

most of the time you want to get the pod so you can log it

just put an extra col in here:

```
Running datums:
ID  STARTED_AT
9ee7b37d-80d2-4b6f-a30b-4c98220e5697  2020-08-25T00:53:05.251386
```

alternative: `falconeri datum log X`