Fix skip_list definition for yamllint
Fix skip_list definition for yamllint

It seems recent update of ansible-lint no longer allows us to use
top-level name but only accepts yaml[<name>] syntax to skip yaml lint
checks. This change updates the config file of ansible-lint to ensure
all yaml lint checks are skipped.

This also skips the experimental checks to skip a few errors currently
detected.

Depends-on: https://review.opendev.org/c/openstack/tripleo-ci/+/850893
Change-Id: Icac9f7c4d6501536467e286311dde34cc7cee198

openstack/tripleo-heat-templates,openstack/tripleo-heat-templates