refactor Ansible files

[hvanz]

The goal of this PR is to simplify the scripts by adopting some of Ansible best practices. In particular:

• put many common settings in ansible.cfg,
• organize files in a predefined directory layout, so we can reuse common variables and tasks. Common tasks are now in files under ansible/tasks and common variables, in ansibles/group_vars/all.yaml, which by defaults is included in all playbooks.

[hvanz]

The only relevant task in this playbook for loadrunners is tasks/testapp-clone-repo.yaml, which is already included loader-init.yaml.

[greg-szabo]

We should also disable gathering facts in playbooks that don't use it.

[greg-szabo]

The ultimate solution would be to minimize the need for ansible. Unfortunately, this is not completely possible as we need to ship files to/from the hosts.

I'd love to see a remote docker-compose solution to manage the hosts services, instead of systems services. Maybe on a deep-flow week we can play with that.

[hvanz]

I agree @greg-szabo. I did this refactoring while trying to understand the scripts. In the long run I hope this simplification of the code will help us to move away from this repo.