lima-kilo: add more robust userconfig support
Add a new 'userconfig' role that contain a never-fail action to load variables from a pre-defined local user file.
Previous to this patch, the user would have need to touch
the a playbooks/vars/local.yaml
file, otherwise the playbook run would fail.
With this patch, we import the local settings only if they exist and use the defaults otherwise.
Bug: T326789 Signed-off-by: Arturo Borrero Gonzalez aborrero@wikimedia.org