i-8 Implements image creation and publishing in playbook (#22)

# Issue

This PR implements the-liberated-edge/test_linux_containers#8

# Acceptance criteria

- [x] The existing playbook has been amended, so that it creates and publishes container images to an incus server running locally.
- [x] Container image name has been parameterised and provided as an Ansible variable.

Co-authored-by: Emil <emil@theliberatededge.org>
Reviewed-on: #22

roles/linux_container/defaults/main.yml

@@ -1,2 +1,3 @@
 ---
 lte_debian_version: bookworm
+lte_container_state: present