Allow users to leverage Gradle build cache

[iamdanfox]

The Gradle build cache is a cache mechanism that aims to save time by reusing outputs produced by other builds. The build cache works by storing (locally or remotely) build outputs and allowing builds to fetch these outputs from the cache when it is determined that inputs have not changed, avoiding the expensive work of regenerating them.

All our compilation should be deterministic, so we should be able to mark these tasks as cacheable!

https://docs.gradle.org/current/userguide/build_cache.html#sec:task_output_caching_details