[RinseFM] - Add: Artist episodes playlist

[SirElderling]

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Description of your pull request and other information

This PR extends the original extractor #8778 with the ability to extract all the episodes for a given artist as a playlist.

To keep it simple, the extraction of the episodes relies on the original RinseFMIE class.
As such, no additional error handling (ex. media not found; page not found) was added.

Template

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• Fix or improvement to an extractor (Make sure to add/update tests)
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[seproDev]

Since the data on the show pages contains all the same data as extracted by RinseFMIE, I think it would be better to return the entries directly instead of using URL results.
For that, move the entry to info dict parsing code in to a base class. Use that function in both RinseFMIE and RinseFMArtistPlaylistIE.

For large playlists, this will be able to save a bunch of HTTP requests.

[SirElderling]

Since the data on the show pages contains all the same data as extracted by RinseFMIE, I think it would be better to return the entries directly instead of using URL results. For that, move the entry to info dict parsing code in to a base class. Use that function in both RinseFMIE and RinseFMArtistPlaylistIE.

For large playlists, this will be able to save a bunch of HTTP requests.

Thanks for the suggestion. I adjusted the code to reflect this change.