Allow specifying fallback view for a user

[singpolyma]

To use instead of gray circle

[matthewrfennell]

I think this could be allowed in a general way by having a view builder for the avatar, which provides a User and expects you to return a View.

This could also enable other things too:

• Creating a fallback of the user's initials as an actual view instead of having to create an image first
• Different fallback views for different users
• Different colouring of the view depending on whether they are currently online, etc.

What do you think?

[f3dm76]

Hey @matthewrfennell, good idea. I don't have time right now, but I'll put it on my to-do list. Have a great day, guys