Declarative S3 cleanup script

This script is essentially the inverse of aliPublish: it takes a config with versions of packages it can delete, and then resolves dependencies and deletes anything that isn't still in use.

Run ./repo-s3-cleanup --help to see options.

The basic operation to delete packages declared in cleanup-rules.yaml is:

./repo-s3-cleanup --do-it cleanup-rules.yaml

It is probably best to run this script manually when needed, e.g. when deleting new batches of old tags. Then, update the configuration and run repo-s3-cleanup without the -y/--do-it option to see what would be deleted, until you're certain that everything is correct.

If a package is not listed for deletion, but it should be, look for ... blocked by ... lines in the output. They will tell you what still depends on the package you want to delete.