Remove orphan instances from Control.ResourceRegistry

We could remove https://github.com/IntersectMBO/io-classes-extra/blob/aee49dd2ebc363f8835534d4f111cf026d99f24d/resource-registry/src/Control/ResourceRegistry.hs#L1492 simply by using a newtype in the `registryAges` field. Seems worth it, in my opinion.