There's a lot here:
- uses Taskcluster YAML v1
- splits the libs/ tasks and caches them by the hash of the libs/ directory
- uses decisionlib to streamline task graph creation
- uses new `application-services-r` worker type
- uses many Taskcluster caches to greatly improve inter-task sharing
of results (via sccache, Gradle caching, and Cargo caching)
This maintains the existing:
- Docker images
- publication to nalexander's personal bintray repository