fix: pre-pull Rancher images and reset Rancher release during bootstrap

Rancher installs were stalling on transient Docker Hub TLS handshake timeouts
for rancher shell, webhook, and system-upgrade-controller images. Pre-pull the
required images onto all nodes after k3s comes up, extend the Rancher HelmRelease
timeout, and reset/force the Rancher HelmRelease before waiting on addon-rancher
so bootstrap can recover from stale failed remediation state.

ansible/site.yml

@@ -93,6 +93,13 @@
   roles:
     - k3s-agent
 
+- name: Pre-pull Rancher bootstrap images
+  hosts: cluster
+  become: true
+
+  roles:
+    - rancher-image-prepull
+
 - name: Deploy observability stack
   hosts: control_plane[0]
   become: true