Cleanup istio-testing GCS buckets
Currently using a LOT of data
artifacts.istio-testing.appspot.com: 39.933TiB - this is gcr.io/istio-testing, contains our per-commit builds among others
Old (1.3) daily/monthly releases istio-presubmit-release-pipeline-data: 33.151TiB - artifacts artifacts.istio-prerelease-testing.appspot.com: 4.947TiB - docker images
Prow logs istio-prow: 17.794TiB
Proxy builds istio-build: 15.457TiB istio-artifacts: 11.007TiB
Old 2017 logs e2e-testing-log: 887.949GiB istio-logs: 200gb
The most likely candidates here are the old monthly builds and the old prow logs. Both of these may not be worth the cost of removal though.
If we really wanted to optimize space, which I don't think we need to, the istio-build/istio-artifacts probably has some junk, but previously we accidentally deleted some important files there so probably best not to touch it
If we are certain the old monthly builds and old prow logs are not needed, shall we just configure retention policy?
This has still not been done, probably useful to do