Add expected_duration to api/v1/episodes

For the API fetch: http://127.0.0.1:8089/api/v1/episodes the 'duration' field represents the actual duration of the recording.

I understand there is a 'corrupted' field but one of the most effective ways I've found of determining if something went wrong with a recording is if the actual duration is far off from the expected duration.

If I have the job where it was recorded, it has the expected duration. But this is a roundabout way to compare the two. Please add "expected_duration" to the episodes fetch.

Thanks