Refactor TOS logic

[fortuna]

This moves application logic out of the ui components. Also, stops using the hidden approach and uses a dialog instead, which is a more maintainable pattern.

[alalamav]

I think the dialog would look better with some more spacing between the image and the text. Also, the unit tests are failing, presumably due to the refactor?

[fortuna]

Ugh, I found out what the problem is: the tests don't define localStorage. I'll need to figure out what to do after I'm back from RightsCon.

[JonathanDCohen]

@fortuna do you still want to do this?