`principalId` i.e user identity is kept as AccessKey in
accordance with S3 spec.
Additionally responseElements{} are added starting with
`x-amz-request-id` is a hexadecimal of the event time itself in nanosecs.
`x-minio-origin-server` - points to the server generating the event.
Fixes#3556
This patch brings in the removal of debug logging altogether, instead
we bring in the functionality of being able to trace the errors properly
pointing back to the origination of the problem.
To enable tracing you need to enable "MINIO_TRACE" set to "1" or "true"
environment variable which would print back traces whenever there is an
error which is unhandled or at the handler layer.
By default this tracing is turned off and only user level logging is
provided.
Harshavardhana