fix(bootstrap): keep package cache off the 2 GiB CIS /var during install

roles/cleanup/tasks/unmount.yml

@@ -2,6 +2,16 @@
 - name: Unmount Disks
   become: true
   block:
+    - name: Unmount the bootstrap package cache
+      ansible.posix.mount:
+        path: /mnt/var/cache
+        state: unmounted
+
+    - name: Remove the bootstrap package cache so it is not sealed into the image
+      ansible.builtin.file:
+        path: /mnt/.bootstrap-cache
+        state: absent
+
     - name: Disable Swap
       ansible.builtin.command: swapoff -a
       register: cleanup_swapoff_result