Improve banned user handling

[Sereri]

If you're banned, almost all forums pages redirect you to a big THANKS AND FUCK OFF page with that photo of Lowtax in hospital on it, as well as links to your Leper's Colony page, the rules, the unban purchase in the SA store, the list of mods/contact info and a log out button. The app isn't able to account for that so it shows the normal top level UI, but returns empty lists of threads. Might be worth putting something similar in to handle that situation.

[sockbot]

Is there a way to see what the banned user is served without being banned? I don't have a banned account to reproduce this behaviour on the website.