add redirect param to login page for loads where user already has cookie

[dr-frmr]

Problem

Hosting service needs to usher user through login page when booting straight into an app

Solution

Add function for login page to allow redirect parameter in url

Testing

1. Boot a node, try navigating straight to app
2. Forced to log in
3. Instead, POST request to /login?redirect=x with credentials and then navigate straight through