*OAuth2 Integration*\nWhen integrating with an OAuth provider like AWS Cognito, how does one set specific roles to specific users?\nOne I set `AUTH_TYPE = AUTH_OAUTH`  I can no longer use the admin user created by `superset fab create-admin`\n\nAlso, `AUTH_ROLE_ADMIN = 'Admin'`  does not make the user signed in via OAuth have admin privileges.