Allow viewing stream topic list from main page

[WesleyAC]

In #4529, we mentioned the possibility of viewing the stream topic list from the main page, without looking at the main stream view first:

Perhaps tapping on the stream name in the main view should bring up the topic list instead of all messages view, or something like that. But that seems more likely to frustrate people (as we've seen with Recent Topics on the webapp) and not super high priority.

I think a good UI for this would be long-pressing the stream name in the main view bringing up an actionsheet with the following options:

• View stream topics
• Mark stream as read
• Mute/Unmute stream
• Unsubscribe
• View stream info (not sure what the name should be, but the same thing that the ⓘ button does right now)
• Cancel

This gives people easy access to a handful of common/useful actions, and neatly solves the problem mentioned in #4529, without breaking any existing behaviour.

[gnprice]

I agree, that sounds helpful.

[vaibhavs2]

I am working on it, assign this to me please

[WesleyAC]

@vaibhavs2 it's probably best not to work on this until #4541 is merged, since that changes what this kind of code will look like a lot.