Java runtime normalized cache

Add normalized cache support to Apollo Java. One question is whether we can keep the normalized cache decoupled like we did in Apollo Kotlin. It's harder to do because Java doesn't have extension functions.

Start by reviewing how normalized caching is decoupled in Apollo Kotlin, then inspect the Java support API to determine how the lack of extension functions affects that design. Done means agreeing on and implementing normalized cache support for the Java runtime with a suitably decoupled integration.

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