Troubleshooting guidance for etcd

[dkeightley]

Unsure if this is the correct area, however, it would be nice to have an official public reference for RKE2 etcdctl commands (via crictl or kubectl) like those detailed here.

As an example the RKE steps are detailed in the Rancher documentation.

This could be a wider series of troubleshooting doc updates, but etcd has probably the highest interest.

[dereknola]

etcd is managed by RKE2; we do not want to encourage people to interact with it directly. We specifically avoid any mention of how to access the embedded etcd via etcdctl for this reason.