No longer necessary now that we're on v1alpha4. Test coverage for
v1alpha4 and the user facing guides will be added back soon for use both
in the holos repo and in Unity.
PGO uses plain yaml and kustomize as the recommended installation
method. Holos supports upstream by adding a new PlainFiles component
kind, which simply copies files into place and lets kustomize handle the
generation of the api objects.
Cue is responsible for very little in this kind of component, basically
allowing overlay resources if needed and deferring everything else to
the holos cli.
The holos cli in turn is responsible for executing kubectl kustomize
build on the input directory to produce the rendered output, then writes
the rendered output into place.
