ci/freedreno: use http cache for traces and document its setup.
In preparation for running valve games in traces CI, we need to cache our downloads to reduce bandwidth usage.
Due to an influx of spam, we have had to impose restrictions on new accounts. Please see this wiki page for instructions on how to get full permissions. Sorry for the inconvenience.
In preparation for running valve games in traces CI, we need to cache our downloads to reduce bandwidth usage.