Add microservice to provide iunreg-like behavior

[alanking]

• main
• 4-3-stable

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Feature

We should add a microservice which allows the caller to do things similar to iunreg.

We have microservices for unregistering a data object and removing a collection, but one cannot target a collection to unregister the data objects (or specific replicas of said data objects) within.

The following features should be supported:

• Targeting collections to unregister
• Targeting specific replicas by replica number
• Targeting specific replicas by source resource

It may make sense to support these features via multiple microservices. It may also make sense to deprecate some existing microservices or some features of said microservices in favor of these new microservices.