* DOCS-1126 draft auth mapping UI docs

* DOCS-1126 add screen cap

* DOCS-1126 add screen cap

* Note about 'bouncing' users without mapping

* small reword

* feedback

Co-authored-by: Kaylyn <kaylyn.sigler@datadoghq.com>

* change important note

Co-authored-by: Ali Sajjadi <github@artificialsanity.net>
Co-authored-by: Kaylyn <kaylyn.sigler@datadoghq.com>