[iOS] Feature improvements: stick groups, group icons, navigation changes

[gdavis]

From Wolfgang in Germany:

1. Sticky group names: I‘ve a lot of podcasts in my groups and when scrolling on the iPhone I would like to see the name of the current group on top of the screen. So I have not to scroll up again to collapse it.
2. Exclude group names from Sorting: I use groups for categories like news or science. It would be great if they are always in the same order. But the included podcasts should be sorted by recently added episodes.
3. Alternative navigation: instead of collapsing/expanding an option would be nice to have a nested view. Tapping a group will slide in its contents so I can swipe to go back to my group list.
4. Custom Icons for groups: As I have a lot of groups, I use Emojis to find them more quickly. Some emojis do harm the alphabetical sorting. What about option to let me choose an group Icon, maybe by using SF Symbols or just Emojis but independently form the group name.
5. An option to show absolute dates instead of relative dates like „days ago“.