i-1 Introduces an Ansible playbook for linux-container with SSH access

# Issue

This PR implements the following [issue](the-liberated-edge/test-linux-containers#1).

# Acceptance criteria

- [x] A playbook for launching LXD Debian container with parameterized container name and OS version has been implemented.
- [x] The newly launched Linux containers can be connected to and administered via SSH.
- [x] The playbook has been part of an Ansible collection named theliberatededge.test_linux_containers.
- [x] Setup and getting started technical documentation has been added to README.md.

Co-authored-by: emo <esimeonov@gmail.com>
Reviewed-on: #2

extensions/molecule/default/verify.yml

@@ -0,0 +1,33 @@
+---
+- name: Verify
+  hosts: localhost
+  gather_facts: false
+  tasks:
+    - name: find current container state
+      ansible.builtin.command: lxc ls {{ item.name }}
+      register: state
+      with_items: '{{ molecule_yml.platforms }}'
+    - name: verify launched container is running
+      ansible.builtin.assert:
+        that: state.results[0].rc == 0 and "RUNNING" in state.results[0].stdout
+    - name: find container ip address
+      ansible.builtin.command: lxc ls -c=4 -f=compact {{ item.name }}
+      register: ipv4_raw
+      with_items: '{{ molecule_yml.platforms }}'
+    - name: set ipv4 address string as a fact
+      ansible.builtin.set_fact:
+        ipv4: '{{ ipv4_raw.results[0].stdout_lines[1] }}'
+    - name: extract ipv4 address of the linux container
+      ansible.builtin.set_fact:
+        ipv4: "{{ ipv4 | regex_search('([0-9]+.[0-9]+.[0-9]+.[0-9]+)') }}"
+    - name: load root password from environment variable
+      ansible.builtin.set_fact:
+        pwd: "{{ lookup('ansible.builtin.env', 'LTE_CONTAINER_ROOT_PWD') }}"
+    - name: connect via ssh to linux container
+      ansible.builtin.shell:
+        cmd: |
+          sshpass -p{{ pwd }} ssh -o ConnectTimeout=1 root@{{ ipv4 }} exit;
+      register: ssh
+    - name: verify ssh connection to linux container
+      ansible.builtin.assert:
+        that: ssh.rc == 0