Simple front page for provision back end.

This is a very simple front page that will do the following :

1. If this platform has not yet been configured, instruct the user to
a: add the platform to a hosting system
b: or run the provision setup command by hand. (http://drupal.org/node/321944)
2. If the platform has been configured :
a: if the platform is managed by a hosting system, redirect to a site-status page on the platform (which will say that it's been disabled, or hasn't been created yet .. would you like to create it?)
b: Display a basic site not found error message.

This is the page that will be directed to by the headless install profile.