Addition of useragent field into quay logging

OpenShift product team and CCX has a need to identify customers who are syncing OCP4 images from quay.io with the intent of standing up a disconnected cluster.

To do this, we need to be able to obtain information, either by parsing access logs or using the log export API to retrieve pulls for specific containers, filtered by the useragent of the client and the access token of the requester.

To achieve the above, the useragent field should be added into the logs for the Quay product and applied to quay.io.

Specific to our use case, the user agent we are interested in is here and here.