Configuring NFS as a cinder backend, and also for glance and nova in OSP 7

Issue

The RHEL OSP7 installation and usage guide in section 6.2.5 describes how to configure the overcloud to use NFS by customizing the ~/templates/my-overcloud/environments/storage-environment.yaml file. Need to also configure heat to configure NFS storage for glance and nova during stack deployment. Glance and nova are mentioned in storage-environment.yaml but the nova section seems incomplete.