detailed stream for episodes and podcasts separated

[woolfg]

• created the API for detailedstreams for episodes
• separated detailedstreams for episode and podcast
• as the spotify APIs are exactly the same, I didn't create a new endpoint. It is the same just with the additional episode_id in the json. This simplifies the API and results in less code.

[woolfg]

DB changes for this PR https://app.planetscale.com/services-openpodcast/openpodcast/deploy-requests/6

[mre]

Looks good to me!

[woolfg]

planetscale PR 6+7 deployed