Improve installer by adding extra OAuth fields to the model/migration stubs when OAuth is installed

[iamdadmin]

Description

Per the documentation, the following fields are exposed from an OAuth user

$user = $this->oauth->fetchUser($code);

$user->id;         // The unique identifier for the user from the OAuth provider
$user->email;      // The user's email address
$user->name;       // The user's name
$user->nickname;   // The user's nickname/username
$user->avatar;     // The user's avatar URL
$user->provider;   // The OAuth provider name
$user->raw;        // Raw user data from the OAuth provider

When launching ./tempest install auth --oauth and the user chooses yes for migrations and user model, we could supply a stub with these additional fields.

Making the question Do you want to install OAuth? Yes/no the first question in the installer may be appropriate also, in the case of the --oauth value not being specifically passed.

Benefits

Smoother developer experience, as invariably this code would be required immediately anyway.

[iamdadmin]

I'm happy to PR this as long as you want the code!

[brendt]

Feel free to send a PR :)