Update notes for submitted changes

* Set nova's default_floating_pool setting.
Update notes for submitted changes

* Switch to using refresh-env.
Update notes for submitted changes

* Remove obsolete docs about iptables.
Update notes for submitted changes

* Document tripleo-cd configuration.
Update notes for submitted changes

* Support working with neutron host-routes.
Update notes for submitted changes

* Use kvm for the cd-overcloud.