Use country_select gem to pick country codes
Use address fields on student signup page
Remove obsolete admin user edit UI
Deprecate user.address_text for address.text

Move to address text being stored on the Address model. In cases where
the address parts have been filled out, update the text from the parts.
Take errors out of address form for now

We’re not using them and this is making the partial more complicated
Format empty addresses as blank strings
Use full address form on new/edit request
Include id in address form

So it doesn’t create a new address entity every time.
Simplify tests a bit with Address#to_params
Use all address fields on fix-flag form
Get rid of last address_text setters
Update address text manually, not automatically

We don’t actually always want to do this. In particular, we’re going to
backfill some addresses, and I don’t want to overwrite the original data
with geocoded data.
Add address backfill