Add composer files (composer.json composer.lock) to define project dependencies

Add composer files (composer.json composer.lock) to define project dependencies.

This Drupal distribution will be defined in the composer.json / composer.lock files.

Together with the docker-compose.json and Dockers files, this will form a standard, repeatable, environment, for both production, development, test, staging and feature branches for your instance of this distribution.

No more table-flip moments when a fellow dev says: "Works-for-me" / "I'm alright Jack." No: "Works for ALL of us".

Thank you.