improve documentation for on premise user using online_sync
https://docs.google.com/document/d/1xGcnM23xLO3bYY1BQrDG-8qRdOh9YUGWR8AoKOcwWXc/edit
https://docs.google.com/document/d/18yM14913EqegeEsYegzP7G-LkQfPUDitRsKhGkS0USQ/edit