Changes to Create external storage

added the optional property cooldown_remaining_ms to the response with the 400 status

added the optional property cooldown_remaining_ms to the response with the 429 status

added the new optional request property aws_s3/s3_custom_endpoint_url

added the optional property unrecoverable to the response with the 400 status

added the optional property unrecoverable to the response with the 429 status

request property storage_type was restricted to a list of enum values

added the new abs enum value to the request property storage_type

added the new gcs enum value to the request property storage_type

added the new s3 enum value to the request property storage_type

endpoint added