UX for handling Direct Messages

[ara4n]

We now have first-class support for direct messages in Vector-web.

It's very unclear on how the UX should work on mobile however. It doesn't seem right to put DMs in their own sublist of the main rooms, so instead we need to apply an icon or something to show which are which.

[ara4n]

See #606 for the implementation side of this.

[benbreckler]

In recents we already have direct messages and group messages mixed. How should this be different? https://zpl.io/3AHRf

[ara4n]

I don't have a clear idea of how we should differentiate DMs from Rooms. Separating them into different lists feels like a mistake on iOS - i.e. the current behaviour is probably correct there. Suggestions for how to better differentiate welcome.

[benbreckler]

I agree. I think the way it currently works on iOS is correct. I don't know if there are any other changes to make here?