Option to mark episode as finished

[SirBogner]

Clear and concise description of the problem

Add an option to mark an episode as finished.

Suggested solution

The button could be placed next to "download podcast" on the podcast overview page.

Alternative

No response

Additional context

No response

Validations

• [X] Follow our Code of Conduct
• [X] Read the Contributing Guide.
• [X] Check that there isn't already an issue that request the same feature to avoid creating a duplicate.

[SamTV12345]

Added. There is now a button that marks an episode as already listened to.