Add a virtually empty ConfigMap that is mounted inside the workers.
Makes it easier to start customizing the worker deployment e.g. with just:
$ kubectl -n ${NFD_NS} edit configmap nfd-worker-conf
Create a new 'templates' make target for inserting the content of
nfd-worker.conf.example into the configmap spec of the templates. Thus,
'make templates' should be run whenever the example config is update.
Update the verify.sh prow script to check that the templates are up to
date.
This patch also streamlines the documentation about configuration
management, reflecting the changes.
