Remove router set up from the wizard

Remove the ability to set up routers in the wizard. Instead rely on the routing page.

Please check out the screen shots here for an explanation of what needs to change in the front end:
https://docs.google.com/a/praekeltconsulting.com/document/d/1y1JTMqC9FDjFJa4sXjaHUsMFGybIdPiN6TLjep4HfUk/edit
Happy for that to happen but preferably in a different PR (at least I don't
know off the top of my head what the comment is really about or what the
tests should look like). Happy for it to be this PR if it's small enough.