Expand basic Ansible concepts with explanations and example

[ahlemsh]

This contribution expands the basic_concepts page by adding a structured overview of fundamental Ansible concepts (control node, managed nodes, inventory, modules, tasks, plays, and playbooks). A simple example playbook has been added to illustrate how these concepts relate in practice.

This makes the page more helpful for new users discovering Ansible for the first time.

[ansible-documentation-bot]

Thanks for your Ansible docs contribution! We talk about Ansible documentation on Matrix at #docs:ansible.im if you ever want to join us and chat about the docs! We meet on Matrix every Tuesday. See the Ansible calendar for meeting details. We welcome additions to our weekly agenda items too. You can add the dawgs-meeting tag to a forum topic to bring it up at the next meeting.