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/tasks/container.yml

@@ -3,17 +3,35 @@
   ansible.builtin.command: incus ls {{ lte_container_name }}
   register: container_state
   changed_when: false
+- name: Stop running container
+  ansible.builtin.command: incus stop {{ lte_container_name }}
+  when: >
+    lte_container_state in ['absent', 'stopped'] and
+    'results' in container_state and
+    container_state.results[0].rc == 0 and
+    'RUNNING' in container_state.results[0].stdout
+- name: Remove stopped container
+  ansible.builtin.command: incus rm {{ lte_container_name }}
+  when: >
+    lte_container_state == 'absent' and
+    'results' in container_state and
+    container_state.results[0].rc == 0 and
+    'RUNNING' in container_state.results[0].stdout
 - name: launch debian bookworm linux container
   ansible.builtin.shell:
     cmd: |
       incus launch \
         images:debian/{{ lte_debian_version }}/cloud \
         {{ lte_container_name }}
-  when: (container_state.rc == 1) or ("RUNNING" not in container_state.stdout)
+  when: >
+    lte_container_state == 'present' and
+    container_state.rc == 1 or
+    'RUNNING' not in container_state.stdout
 - name: update apt cache and upgrade system packages
   ansible.builtin.shell:
-    cmd: |-
+    cmd: |
       incus exec {{ lte_container_name }} -- \
         bash -c \
           '/usr/bin/apt update && /usr/bin/apt upgrade -y'
+  when: lte_container_state == 'present'
   changed_when: false

roles/linux_container/tasks/main.yml

@@ -1,4 +1,6 @@
 ---
 - ansible.builtin.include_tasks: container.yml
 - ansible.builtin.include_tasks: ume.yml
+  when: lte_container_state == 'present'
 - ansible.builtin.include_tasks: openssh-server.yml
+  when: lte_container_state == 'present'