[Issue] Automation to clean up eligible release in our various registries (nightly, dev, prod)

To keep our registries clean, we should have a simple bit of automation that can go through and prune out "old" releases, based on some criteria.

* For prod, for instance, we could start expiring older betas once a GA comes out.
* For nightly, we're currently uploading the blobs into an un-versioned location in Azure Storage. We should be clearing out the old entries in the registry.
* Dev might not be growing much, but we can think about what an expiration looks like there. Perhaps the expiration is manual, but the cleanup is automatic.

We're not currently drowning in releases, so this isn't urgent, but it's good to think about how we'll handle it without manual work on our part.

No files, tests, or automation entry points are identified in the issue. Start by defining retention and expiration criteria for the prod, nightly, and dev registries, including Azure Storage entries; the work is done when cleanup can run automatically against agreed criteria without manual registry pruning.

Written by the indexing model from the issue text.