Replace top nav hamburger icon with user avatar when signed in

[machinaeZER0]

I've always liked when apps show my avatar in some fashion when signed in, and often that will be done in a way where tapping the avatar will open a menu. I'd personally love to see the hamburger menu icon in top nav replaced with the user avatar when signed in (as a toggle, probably), which would continue to open the sidebar when tapped!

Not to go down a huge rabbit hole, but I could also see this paving the way toward having a little more personal/user-related info in said sidebar, which would then make this update a little more relevant (if eventually there's the ability to switch accounts from the sidebar, for example). Food for thought, but currently outside the scope of this feature request!