Move login to a 401 page

[ning-y]

The current default landing page is News. If the
user clicks on Source Academy, they are brought
to the 'anonymous' (no associated navigation
button) Game component.

If this user is not logged in, they will receive
a pop-up LoginDialog. However, the Game
component will still render. This possesses a
problem with regards to performance, as well as
data (there is no data in state.session to
indicate username, story...)

Furthermore, we expect similar problems if a user
who is not logged in visits directly, via URL, any
page under Academy.

---

As a solution, we should move the login into its
separate component, 401. When the react router
receives a user request for /academy/*, the
router checks if the user is logged in. If the
user is logged in, the user is routed as per
usual. If not, the user is redirected to the 401
page instead, by-passing the render of Academy
components. When a user successfully logs in via
the 401 page, we call history to return to the
Academy component the user was trying to access.
If the history is empty, default to /academy/game.

[ning-y]

My bad, was on mobile and had the wrong repo open.