New HeaderAuthenticator class that is designed to replace RemoteUserAuthenticator and DataRemoteUserAuthenticator
In addition, the HeaderAuthenticator introduces the following features
- Customisable header definitions for authentication
- Set auth_state data via custom data headers during authentication
- Allow custom parsers of both the authentication and data headers
- Allow auth_state data headers with spawner environment during pre_spawn_hook
- Introduce /user-data URL which allows JSON posts after authentication to provide additional user data.