Distinguish clearly between logged-in and not logged-in states

[txels]

This applies to building proper menus, choosing the initial route, etc.

Currently even if you do not log in via github, you can access internal URLs such as http://192.168.254.184:5000/#/features and data from non-github providers (e.g. sprint.ly) still comes through.

Once you are logged in, the main page should stop being the "marketing page".