Topbar: Use Login

This breaking release of Topbar targets Login instead of Accounts for /logout urls.
All other Accounts urls remain the same.

Thanks @joshwilkerson for making the requisite change 🙌

Migrate

This upgrade requires no app-side interventions.
Here's the v6 migration doc anyway.

Please check with the Login/Accounts team regarding any requisite application changes.

Added Avatar Alpha

Things are happening!

Actually not yet. This is just boilerplate code.