Create an ansible-galaxy role for the system-update role.

We should pull the lf-ansible system-update role into a separate repo and deploy it to ansible-galaxy.

https://github.com/lfit/releng-lf-ansible/tree/master/roles/system-update/tasks

This is the first test of many ansible roles to come.

Detailed documentation can be found here: https://galaxy.ansible.com/intro#share