Don't allow deletes in cluster, account and/or container

In some use cases, such as with original media content, source images, etc., it's desirable to not *ever* allow deleting an object. This blueprint suggestion is similar to a WORM-mode in some ways. While it might not entirely meet the full specs of WORM, it would go a long way towards providing initial functionality good enough for many organizations needing something WORM-like.

Being able to set an entire cluster, one or more accounts and/or containers to not allow deletes would be a great feature for many end-users and applications.

Lastly, if a no-delete flag could be set based on authenticated user, that would be a bonus, but not necessarily very important.