ref(roles): All roles use desired package state

By setting the `desired_package_state` variable we can change if ansible
should only ensure that the packages exist on the system (`present`) or
that they are also updated to their latest version (`latest`).

roles/host/tasks/main.yaml

@@ -10,7 +10,7 @@
 #   tasks:
 #     - name: Create @voidroot subvool under root
 #       community.general.btrfs_subvolume:
-#         state: present
+#         state: "{{ desired_package_state | default('present') }}"
 #         name: "/@"
  #         filesystem_uuid: "{{ btrfs_root_uuid }}"
  #     # - name: Mount /boot part into voidroot mount