Add link to FAQ page in welcome banner.

When a user first visits an Askbot-powered site, she sees an invitation to visit the FAQ in the welcome banner, but there is no link. In fact, the only link to the FAQ page is waaaaaaay down at the bottom of the page!

However, it is trivially easy to add a link to the banner. Simply change the "Text shown in the greeting message shown to the anonymous user" in the "URLS, keywords & greetings" section of Django admin to the following:

First time here? Check out the <a href="/faq/">FAQ</a>!

And voila! You have a link to the FAQ page in the banner inviting new users to visit the FAQ!

This is such a trivially-simple change to implement, and it significantly improves the experience for new users. It might be worthwhile to update the codebase so that the above HTML is the default value for this setting.