Authorization flow should be separated from S3 Authentication flow

[jeniawhite]

Is your feature request related to a problem? Please describe. Currently, the S3 authentication flow is a part of the auth_server authorization flow. This creates a complex authorization mechanism that is much more error-prone and requires delicate handling when there are bugs or required changes/additions to the component.

Describe the solution you'd like These two flows should be separated. The S3 authentication should be handled in addition to the auth_server authorization.