Keeping RustFS clear of old assets

After having RustFS [https://www.mikestreety.co.uk/blog/setting-up-rustfs-as-an-amazon-s3-replacement/] running as our Gitlab CI cache [https://www.mikestreety.co.uk/blog/use-minio-to-cache-gitlab-containers-and-runners/] for a few weeks the server (as expected) filled up. Since we're only using RustFS to cache build assets, we can safely bin the old ones without worry. We settled on a 14-day…