feat: add ChannelRss

- add documentation
- small model refactor: rename player VideoPlayerDetails.thumbnails to thumbnail

src/model/paginator.rs

@@ -2,6 +2,8 @@ use std::convert::TryInto;
 
 use serde::{Deserialize, Serialize};
 
+/// Wrapper around progressively fetched items
+///
 /// The paginator is a wrapper around a list of items that are fetched
 /// in pages from the YouTube API (e.g. playlist items,
 /// video recommendations or comments).