add kbatch job logs

[minrk]

allows getting logs by job name, which is usually what folks have

rather than needing to do job -> pod lookup

(draft because no tests yet)

this and #79 together closes #61 where someone is requesting logs for a job name, not a pod name. #79 makes the error more apparent, while this does what is actually expected (logs for a job)

[minrk]

alternative to this: replace pod logs with job logs, since that's more like what folks are going to want. But maybe jobs can have more than one pod?

[minrk]

I don't think job logs can replace pod logs because things like cronjobs might have more than one pod associated.

[yuvipanda]

Yes, adding this as an addition instead of replacement is the way to go!