Add additional static pod cleanup during cluster reset

[brandond]

Proposed Changes

Addresses issue with hangs or crashes when starting up servers following a cluster-reset, caused by etcd and/or the apiserver being restarted in unexpected sequences.

Background is discussed at #4707 (comment):

• Shut down the etcd static pod (and the kubelet, to keep the kubelet from restarting it) at the end of the cluster-reset process, so that etcd doesn't have to be restarted and reconfigured midway through the next start. Etcd is explicitly shut down at the end of the cluster-reset process on k3s, we just haven't wired up the context on RKE2.
• Remove the apiserver static pod manifest during rke2 startup, so that the kubelet doesn't start it before it's been written with the current config - after etcd starts.
  need to confirm that this doesn't do anything weird during normal restarts of the rke2 service
• Use the absence of etcd db files on a node with etcd enabled as an indicator of cluster-reset, and force cleanup of the etcd and apiserver static pods early on in startup. This prevents them from being restarted later, while the kubelet and embedded controllers are trying to talk to them.

Also updates k3s.

Types of Changes

bugfix

Verification

• See linked issue
• In addition to the steps in the linked issue, should also see some new messages at the end of the cluster-reset process:

  INFO[0067] Shutting down kubelet and etcd
  ERRO[0067] Kubelet exited: signal: killed
  INFO[0072] Managed etcd cluster membership has been reset, restart without --cluster-reset flag now. Backup and delete ${datadir}/server/db on each peer etcd server and rejoin the nodes
  

• Confirm that there is no etcd process running after rke2 exits at the end of the cluster-reset.

Testing

Linked Issues

• During System cluster reset, node is stuck on sudo systemctl start rke2-server for a 45 min #4707
• Observed crash in filtercn address controller #4713

User-Facing Change

Further Comments