- The `scopes_form` partial can be used in the `admin/applications` view
  as well

- Don't allow partials to access instance variables directly. Instead, pass
  in the instance variables as local variables, and use `local_assigns.fetch`
  to assert that the variables are passed in as expected.

- Change a few instances of `render :partial` to `render`

- Remove an instance of `required: false` in a view, since this is the default

- Inline many instances of a local variable (`ip = 'ip'`) in `auth_spec`

- The list of scopes that's displayed while creating a personal access
  token is identical to the list that's displayed while creating an OAuth
  application. Extract these into a partial.

- The list of scopes that's displayed while in the show page for an OAuth token
  in the profile settings and admin settings are identical. Extract these into
  a partial.

- Mainly whitespace changes.

- Require the migration adding the `scope` column to the
  `personal_access_tokens` table to have downtime, since API calls will
  fail if the new code is in place, but the migration hasn't run.

- Minor refactoring - load `@scopes` in a `before_action`, since we're
  doing it in three different places.