Add ability to see hashtags (or other views) from all instances

### Problem I have

When I'm on a hashtag page, I can only see local hashtags ("Go to my instance") or hashtags from one instance ("Go to another instance"). This limits the content I see when searching for a hashtag.

### Solution I'd like

Add another option to ("Go to all federated instances") that shows hashtags from all instances federating with the home instance.

### Alternatives considered

_No response_

### Other

This option might be appropriate for other views such as Trending (I see there is Local and Federated but my experience is that while Local works, Federated shows basically the same content).