Do this in preparation for using more code from the CCCHH/ansible-infra
repo, not just for the docker role.
Also use the current name and repository URL.
Add a docker role for making sure Docker is installed from the Docker
repositories.
Take the role from the ccchh-ansible repo, provide attribution in the
README and add the relevant license in a new licenses directory.
Modify the role by removing the distribution check and adjusting the
task names to be in line with other task names in this repo.
