Allow user to update profile as part of the OAuth flow

- created text fields in the authorizations page that correspond to profile fields from requested scopes
- disabled text fields that are already filled out (can change styling so that they don't look like text fields)
- use profile.update_attributes with whitelisted profile hash to save fields
- model, controller, and capybara tests where appropriate
- removed a few unused methods
- TODO: organize FIELDS and METHODS constants in profile so it's easier to access them elsewhere
i've added support (and a test!) for the sad path.