Use /etc/syconfig/undercloudrc instead of $HOME/undercloudrc.

After this change, we wouldn't need to worry about telling people how to find
undercloudrc if they switch accounts, etc.
Provide an empty /etc/sysconfig/undercloud-live-config.

Makes it easier for the user to know what variables need to be set in their
environment, etc.
Update env vars in undercloud-live-config
Add undercloud-environment element.

Refactors the common pieces out of undercloud-{control,leaf}-config into a
common undercloud-environment element.  Update install scripts to use common
element.
Updated baremetal.sh
Add script to create baremetal vm nodes.