Introduce a UpgradeScriptDeliveryWorfklow as part of tripleo upgrades

Introduce a UpgradeScriptDeliveryWorfklow as part of tripleo upgrades

This splits the upgrade script delivery out of the UpgradeWorkflow
and into a new task which delivers the upgrade script for
compute and object-storage nodes. This is intended to be the first
part of the upgrades process, since we need to upgrade swift nodes
before the controllers and then only one at a time. So this will
deliver the upgrade script which can be invoked by the operator
using the existing script in tripleo-common
'upgrade-non-controller.sh'.

This can be invoked by passing the -e
environments/major-upgrade-script-delivery.yaml (added here) to
the openstack overcloud deploy command.

Change-Id: I20a0d4978e907111404f8108c502ab53b69a3296