Since all the nodes in the cluster run Fedora CoreOS now, we can
deploy collectd as a container, managed by a DaemonSet.
Note that while _collectd_ has to run as _root_ in order to collect
a lot of metrics, it should not run with all privileges. It does need
to run as a "super-privileged container" (`spc_t` SELinux domain), but
it does _not_ need most kernel capabilities.
