Set up login/logout and profile redirect

Django auth, by default, redirects a successful login to
/accounts/profile/. I set up a redirect from /accounts/profile/ to
/users/{logged-in-users-username} so that we have a consistant URL
for viewing both the page for the logged in user and any other user
page.

If a user is not logged in /accounts/profile/ redirects to
settings.LOGIN_URL