Warning when folks using default SystemdCgroup (false) when running in Systemd environments

[dims]

Folks,

We've had folks run into this situation quite a few times:
kubernetes/kubernetes#115581 (comment)

Essentially the default in our config.toml in containerd for SystemdCgroup is false and most of k8s has been the opposite (example kubernetes/kubeadm#2376)

So would we may be at least add a warning in our logs that systemd is ON and their config is NOT reflecting that?

Note there's a handy IsRunningSystemd we can use to check and log a message: https://cs.k8s.io/?q=IsRunningSystemd&i=nope&files=&excludeFiles=&repos=kubernetes/kubernetes

thanks!

[carlory]

/assign