For now everything should look identical. However this moves to using a model for the content of the message and is intended to lay the foundation for improved message content representation, e.g. splitting up a text message in multiple sections and using different delegates for things like code and quotes.
Get rid of the anchors and move to layouts for th bubble and avatars.
This allows the timestamp to be fixed in compact mode so it always sits on the far right. It's also just now more compact than before.
