filter with one episode per postcast

### What problem does this address?

All filters I see are resulting in multiple episodes per podcast. E.g. in New Releases there are a lot of episodes from podcasts that are creating daily, they obscure the podcasts that release less frequently.

### What is your proposed solution?

wish 1: I want to be able to create a filter that is only showing one episode per podcast, the newest or oldest. Is that possible?

wish 2: I would also be able to filter on archived=no, so I could be able to create a filter to make a list all the oldest non-played episodes per subscribed podcasts (I listen to some podcasts in a chronological way).

### Did you search for existing feature suggestions?

- [X] I have searched for existing feature suggestions.

Start by reviewing the existing filter options and the New Releases behavior described in the issue. Determine how filters represent newest or oldest episodes per podcast and the archived=no condition; done means both requested filter patterns work without hiding unrelated podcasts.

Written by the indexing model from the issue text.