Remove unnecessary zuul layout overrides use templates instead
Remove unnecessary zuul layout overrides use templates instead

This removes unnecessary zuul layout overrides. The containers
multinode and standalone/scenarios are already included via the
wired-up templates. Keeps only the undercloud-minion which is not
in the tripleo-multinode-container-minimal-pipeline [1] but updates
the consumer job vars. Part of tripleo-ci optimisation at [2].

[1] https://opendev.org/openstack/tripleo-ci/src/commit/67a58a43788dfff284ec55eff6f4e65c0116160b/zuul.d/multinode-jobs.yaml#L71-L85
[2] https://review.opendev.org/q/topic:tripleo-ci-reduce

Change-Id: I7c4ba85cbc1525079a94cb76aa9576b24f1d0fbb

openstack/python-tripleoclient