[Feature] add 3 panel view design

Is your feature request related to a problem? Please describe.

Personally, I don't like 2 panel designs in rss-readers. In my opinion its not as clean as 3 panel designs. With 2 panels I mean:

• on the left the rss-sources
• on the right article-list and the article opens in the same panel

Use case

No response

Describe the solution you’d like

I would prefer it, if there would be (an optional) 3 panel design:

• on the left the sources
• in the middle article-list
• on the right opens the current article

like on e.g. fluent reader

Describe alternatives you’ve considered

No response

Additional context

No response