Add country selector back

[anth-volk]

For a limited subset of users, we don't correctly capture their location (e.g., one I was talking to today), sending them to the wrong country page. This needs to be fixed, but it's also an inexact science - what if one visits the UK and doesn't know they can change the country code in the URL back to US? Worse, we don't even do it geographically, but by browser language, so what if something's incorrectly configured on the user's end?

We should add a way of selecting country back to the app