Extract AAF Adapter from OTIO core and establish separate git repo (#1348)

* Remove AAF adapter
* Add Note about the AAF adapter being moved

Signed-off-by: Mark Reid <[email protected]>
Signed-off-by: Eric Reinecke <[email protected]>

Author: markreidvfx

README.md

@@ -73,6 +73,9 @@ For more information: https://github.com/AcademySoftwareFoundation/OpenTimelineI
 
 For more information about this, including supported formats, see: https://opentimelineio.readthedocs.io/en/latest/tutorials/adapters.html
 
+The **AAF Adapter** has been **relocated** to a separate repository and is located here:
+https://github.com/OpenTimelineIO/otio-aaf-adapter
+
 Other Plugins
 -------------