Description of problem:

Since the VF has a proper CLI included in validations-libs, it make sense to implement a validation.cfg config file in order to provide severals parameters through it.


For a 1st iteration the goals will be:

* the used of ConfigParser python builtin to avoid too much dependencies and links with other Openstack  projects.

* a minimal set of sections: default / ansible_runner / ansible_environment

The default will be the settings for the CLI parameters.
Ansible Runner, a way to override the ansible runner options
Ansible Environment will expose all the Ansible env variables available in Ansible so the user can edit, update, configure them without export each time those values.

* The precedence of the parameters will be as Ansible CLI does:
    * User CLI parameters take precedence on all the other values
    * The config is loaded on each run if found, and will override the default parameters
example:
config file:
[default]
validation_dir = /home/foo


$ validation run --validation foo --validation-dir /foo/bar
-> validation_dir is /foo/bar

$ validation run --validation foo
-> validation_dir is /home/foo

Config file not found:
$ validation run --validation foo
-> validation_dir is /usr/share/ansible/validation-playbooks