Better UX for person getting kicked out of the group

[cstiens]

Original issue: #369

Even though you've been kicked out you still see the group in your convo view. You do not receive new messages or notifications. And if you check the group roster you are not shown in the roster.

You can open the group from the convo view and see the full group chat. You can send messages, but they don't go through. But, as the person getting kicked out, you don't actually know that you got kicked out.

What can we do for the person that got kicked out?

• send a notification?
• remove the group from their convo view?
• automatically archive the group?